Resin composition, insulating film comprising the same and printed circuit board comprising the same

Abstract

This invention provides a resin composition, an insulating film, and a printed circuit board. The resin composition includes: an epoxy resin; two or more phenolic resins; a thermoplastic resin; and an inorganic filler. The ratio of the epoxy groups in the epoxy resin to the hydroxyl groups in the phenolic resin is from 1:0.5 to 1:0.01. The epoxy resin includes bisphenol-type epoxy resin, phenolic varnish-type epoxy resin, and bixylenol-type epoxy resin. The phenolic resin includes naphthol-containing phenolic resin and triazine-containing phenolic resin, with a weight ratio of naphthol-containing phenolic resin to triazine-containing phenolic resin of 1:2 to 2:1.

Description

[Technical Field]

[0001] This invention relates to resin compositions, insulating films therein, and printed circuit boards.

[0002] This application claims the rights of Korean Patent Application No. 10-2024-0059982 filed with the Korean Intellectual Property Office on May 7, 2024, and Korean Patent Application No. 10-2025-0057668 filed on April 30, 2025, the entire disclosure of which is incorporated herein by reference. [Previous Technology]

[0003] With the miniaturization and increasing performance of electronic devices, multilayer printed circuit boards (PCBs) are gradually becoming multi-layered. In such multilayer PCBs, due to the significant difference in the coefficients of thermal expansion between copper wiring and insulating layers, problems such as cracking of copper wiring or insulating layers may occur during reliability tests such as thermal cycling. Therefore, it is urgent to suppress the thermal expansion rate of the resin composition forming the insulating layer to a low level.

[0004] As one of the means to suppress the coefficient of thermal expansion, inorganic fillers are usually added to the resin composition. As the amount of inorganic filler added increases, the coefficient of thermal expansion is further reduced. However, when the composition contains a large amount of inorganic filler, it is not only difficult to control the viscosity of the coating solution itself, but also, due to the large number of inorganic fillers exposed on the surface after roughening treatment, there is a problem of deterioration in the peel strength of the conductor layer formed by electroplating.

[0005] In order to solve this problem, it is necessary to study a composition that has high peel strength and low thermal expansion rate by using an appropriate amount of inorganic filler.

[0006] [References]

[0007] (Patent Document 1) Korean Patent Publication No. 2012-0107277 [Summary of the Invention]

[0008] [Technical Issue]

[0009] This disclosure aims to provide a resin composition, an insulating film comprising the resin composition, and a printed circuit board.

[0010] [Technical Solution]

[0011] This embodiment of the invention provides a resin composition comprising: an epoxy resin; two or more phenolic resins; a thermoplastic resin; and an inorganic filler, wherein the ratio of the epoxy groups of the epoxy resin to the hydroxyl groups of the phenolic resin is 1:0.5 to 1:0.01, the epoxy resin includes bisphenol type epoxy resin, phenolic varnish type epoxy resin and bixylenol type epoxy resin, the phenolic resin includes naphthol-containing phenolic resin and triazine-containing phenolic resin, and the weight ratio of the naphthol-containing phenolic resin to the triazine-containing phenolic resin is 1:2 to 2:1.

[0012] Another exemplary embodiment of this disclosure provides an insulating film comprising a resin composition or a cured product thereof.

[0013] Yet another exemplary embodiment of this disclosure provides a printed circuit board including an insulating film.

[0014] [Beneficial Effects]

[0015] The resin composition according to an exemplary embodiment of the present invention comprises a naphthol-containing phenolic resin and a triazine-containing phenolic resin as curing agents in a specific weight ratio, comprises three specific epoxy resins, and uses the epoxy resin and phenolic resin in a specific ratio of epoxy groups to hydroxyl groups of the phenolic resin. In this manner, even with a high content of inorganic fillers, the coefficient of thermal expansion can be sufficiently reduced, thereby minimizing reliability-related problems such as thermal cycling in subsequent multilayer printed circuit boards. An excellent insulating layer can also be formed, wherein the conductor layer has an appropriate level or higher peel strength.

[0016] Therefore, the multilayer printed circuit board obtained using the resin composition according to an exemplary embodiment of the present invention has excellent physical properties of thermal expansion coefficient, while exhibiting appropriate surface roughness through desizing treatment, thereby providing high adhesion to copper foil.

Implementation Method

[0018] The contents of this disclosure will be explained in more detail below.

[0019] In this specification, when a component is described as being "on" another component, this includes not only the case where the component is in contact with the other component, but also the case where there is another component between the two components.

[0020] In this specification, when a description part "includes" a component, this does not exclude the presence of another component, but rather implies that further components may be included, unless the context specifically indicates otherwise.

[0021] In this specification, "from A to B" or "AB" means a range that is equal to or greater than A and equal to or less than B.

[0022] As a method for manufacturing multilayer printed circuit boards, a method of alternately laminating conductor layers and insulating films has been developed and is currently used in semiconductor packaging. In the manufacturing process of multilayer printed circuit boards, the laminated insulating films are first vacuum-laminated onto the inner layer circuits, followed by pre-curing → drilling → desmearing → electroless plating → electroplating → post-curing → formation of the outer layer circuits. Here, the desmearing step functions to create surface roughness by removing the desmears with an acidic solution and simultaneously etching a certain amount of the insulating film surface, which increases the adhesion to the copper foil layer formed in subsequent steps.

[0023] Compositions containing epoxy resin and phenolic curing agents, and containing inorganic fillers added thereto, have been used as resin compositions for laminated insulating films. However, when increasing the amount of inorganic filler added to obtain the desired coefficient of thermal expansion, it is difficult to control the viscosity of the coating solution, and the inorganic filler is overexposed on the surface after roughening treatment, resulting in a decrease in peel strength.

[0024] In this context, the object of this disclosure is to provide a resin composition that uses an appropriate amount of inorganic filler to obtain a desired coefficient of thermal expansion and has high peel strength, and a printed circuit board comprising said resin composition.

[0025] In an exemplary embodiment of the present invention, the resin composition includes: an epoxy resin; two or more phenolic resins; a thermoplastic resin; and an inorganic filler, wherein the ratio (composition ratio) of the epoxy groups of the epoxy resin to the hydroxyl groups of the phenolic resin is 1:0.5 to 1:0.01, the epoxy resin includes bisphenol type epoxy resin, phenolic varnish type epoxy resin and bixylenol type epoxy resin, the phenolic resin includes naphthol-containing phenolic resin and triazine-containing phenolic resin, and the weight ratio of naphthol-containing phenolic resin to triazine-containing phenolic resin is 1:2 to 2:1.

[0026] The constituent elements of this disclosure will be explained below.

[0027] Epoxy Resin

[0028] In an exemplary embodiment of the present invention, the epoxy resin includes: bisphenol type epoxy resin; phenolic varnish type epoxy resin; and xylenol type epoxy resin.

[0029] In an exemplary embodiment of the present invention, the bisphenol type epoxy resin may be bisphenol A type epoxy resin, bisphenol F type epoxy resin or bisphenol S type epoxy resin.

[0030] In an exemplary embodiment of the present invention, the bisphenol type epoxy resin may be selected from YD-113, YD-114, YD-114E, YD-114F, YD-115, YD-115G, YD-115CA, KD-1818, YD-127, YD-128, YD-128S, YD-134, YD-136 (Kokto Chemical Co., Ltd.), EXA-4850-150, EXA-4850-1000 (DIC), etc., but is not limited thereto.

[0031] In an exemplary embodiment of the present invention, the phenolic varnish-type epoxy resin may be selected from YDPN-638, YDPN-639, KT-7804 (Kokto Chemical Co., Ltd.), etc., but is not limited thereto.

[0032] In an exemplary embodiment of the present invention, the bis(xylenol) type epoxy resin may be selected from YX-4000H, YX-4000, YX-4000HK, YL-7890 (Mitsubishi Chemical Corporation), etc., but is not limited thereto.

[0033] In one exemplary embodiment of the present invention, the resin composition may comprise four or more types of epoxy resins.

[0034] In an exemplary embodiment of the present invention, the resin composition may further include additional epoxy resins in addition to bisphenol type epoxy resin, phenolic varnish type epoxy resin and bixylenol type epoxy resin.

[0035] In an exemplary embodiment of the present invention, any epoxy resin known in the art can be used as the additional epoxy resin without particular limitation, but the additional epoxy resin preferably has two or more epoxy groups in one molecule. More specifically, the epoxy resin may be selected from: naphthylene-type epoxy resin; anthracene-type epoxy resin; biphenyl-type epoxy resin; tetramethylbiphenyl-type epoxy resin; cresol varnish-type epoxy resin; bisphenol A varnish-type epoxy resin; bisphenol S varnish-type epoxy resin; biphenyl varnish-type epoxy resin; naphthol varnish-type epoxy resin; naphthol-phenol cocondensation varnish-type epoxy resin; naphthol-cresol cocondensation varnish-type epoxy resin; aromatic hydrocarbon formaldehyde resin modified phenol resin type epoxy resin; triphenylmethane-type epoxy resin; tetraphenylethane-type epoxy resin; dicyclopentadienylphenol addition-type epoxy resin; phenol aralkyl-type epoxy resin; naphthol aralkyl-type epoxy resin, etc.

[0036] In an exemplary embodiment of the present invention, the total content of the epoxy resin may be 10-30 parts by weight, based on the total solids content of 100 parts by weight of the resin composition.

[0037] In an exemplary embodiment of the present invention, the total content of the epoxy resin may be 20-27 parts by weight, based on the total solids content of 100 parts by weight of the resin composition.

[0038] When the epoxy resin content in the resin composition falls within the above-defined range, the moldability and processability are improved, and the physical properties required to form a suitable roughness can be ensured in the descaling step.

[0039] In an exemplary embodiment of the present invention, the contents of bisphenol type epoxy resin, phenolic varnish type epoxy resin and bixylenol type epoxy resin are not particularly limited, as long as the total content range of epoxy resin as defined above is met, and the ratio range of epoxy groups of epoxy resin to hydroxyl groups of phenolic resin as defined above is also met.

[0040] In an exemplary embodiment of the present invention, the resin composition may include, based on 100 parts by weight of total epoxy resin, 10-30 parts by weight of bisphenol type epoxy resin; 40-60 parts by weight of phenol type epoxy resin; and 20-40 parts by weight of bixylenol type epoxy resin.

[0041] In an exemplary embodiment of the present invention, the resin composition may include, based on 100 parts by weight of total epoxy resin, 10-30 parts by weight of bisphenol type epoxy resin; 20-40 parts by weight of phenol type epoxy resin; and 40-60 parts by weight of bixylenol type epoxy resin.

[0042] Phenolic resin

[0043] In an exemplary embodiment of the present invention, the resin composition comprises two or more phenolic resins, wherein the phenolic resins include naphthol-containing phenolic resin and triazine-containing phenolic resin, and the weight ratio of the naphthol-containing phenolic resin to the triazine-containing phenolic resin is 1:2 to 2:1.

[0044] In an exemplary embodiment of the present invention, phenolic resin acts as a curing agent in the resin composition and may be referred to as a phenolic curing agent.

[0045] This resin composition uses two specific types of phenolic resins within the above weight ratio range as curing agents, thereby preventing the decrease in peel strength caused by the use of inorganic fillers.

[0046] In an exemplary embodiment of the present invention, the weight ratio of the naphthol-containing phenolic resin to the triazine-containing phenolic resin is 1:1 to 2:1, preferably 1:1 to 1.8:1.

[0047] In an exemplary embodiment of the present invention, the naphthol-containing aldehyde resin may include a structure represented by the following chemical formula 1: [Chemical Formula 1] In chemical formula 1, X1 and X2 represent the same or different from another structure, and each independently represents a divalent organic group, a and b are the same or different, and each independently represents an integer from 1 to 6, and n is an integer from 1 to 20.

[0048] In one exemplary embodiment of the present invention, X1 and X2 may be the same or different, and each may independently represent a substituted or unsubstituted alkylene group; a substituted or unsubstituted aryl group; or a substituted or unsubstituted divalent amino group.

[0049] In one exemplary embodiment of the present invention, X1 and X2 may be the same or different, and each may independently represent a substituted or unsubstituted C1-C30 alkylene group; a substituted or unsubstituted C6-C30 aryl group; or a substituted or unsubstituted divalent amino group.

[0050] In an exemplary embodiment of the present invention, a and b may be the same or different, each independently representing an integer from 1 to 6, preferably an integer from 1 to 4, more preferably an integer of 1 or 2, and most preferably 1.

[0051] In an exemplary embodiment of the present invention, when n is an integer of 2 or greater, the structure of the repeating units in the parentheses may be the same or different.

[0052] In one exemplary embodiment of the present invention, the end group of the naphthol aldehyde resin may be a hydrogen atom; a hydroxyl group; an ester group; a cyanate ester group; a substituted or unsubstituted alkyl group; or a substituted or unsubstituted aryl group, but is not limited thereto.

[0053] In this specification, ester group may refer to active ester group. Active ester group is an ester functional group that is sensitive to nucleophilic attack, and may be a normal ester type with modified acetyl or alkoxy moieties.

[0054] In one exemplary embodiment of the present invention, the end group of the naphthol aldehyde resin may be a hydrogen atom; a substituted or unsubstituted C1-C30 alkyl group; or a substituted or unsubstituted C6-C30 aryl group, but is not limited thereto.

[0055] In one exemplary embodiment of the present invention, the naphthol-containing aldehyde resin may include SN-395, SN-485, SN-395 (Nippon Steel Chemical Co., Ltd.), etc., but is not limited thereto.

[0056] In an exemplary embodiment of the present invention, the triazine-containing phenolic resin may include the structure represented by the following chemical formula 2: [Chemical Formula 2] In chemical formula 2, X3 and X4 represent the connection site with another structure, X3 and X4 are the same or different and each independently represents a divalent organic group, R1 represents a hydrogen atom; substituted or unsubstituted alkyl; substituted or unsubstituted aryl; or substituted or unsubstituted amino, c and d are the same or different and each independently represents an integer ranging from 1 to 4, and m is an integer ranging from 1 to 20.

[0057] In an exemplary embodiment of the present invention, R1 may be a hydrogen atom; a substituted or unsubstituted C1-C30 alkyl group; a substituted or unsubstituted C6-C30 aryl group; or a substituted or unsubstituted amino group.

[0058] In one exemplary embodiment of the present invention, X3 and X4 may be the same or different, and each may independently represent a substituted or unsubstituted alkyl group; a substituted or unsubstituted aryl group; or a substituted or unsubstituted divalent amino group.

[0059] In one exemplary embodiment of the present invention, X3 and X4 may be the same or different, and each may independently represent a substituted or unsubstituted C1-C30 alkyl group; a substituted or unsubstituted C6-C30 aryl group; or a substituted or unsubstituted divalent amino group.

[0060] In an exemplary embodiment of the present invention, c and d may be the same or different, and each independently represents an integer ranging from 1 to 4, preferably from 1 to 3, more preferably an integer of 1 or 2, and most preferably 1.

[0061] In an exemplary embodiment of the present invention, the end group of the triazine phenolic resin may be a hydrogen atom; a substituted or unsubstituted alkyl group; or a substituted or unsubstituted aryl group, preferably a hydrogen atom or a methyl group.

[0062] In an exemplary embodiment of the present invention, the end group of the triazine phenolic resin may be a hydrogen atom; a substituted or unsubstituted C1-C30 alkyl group; or a substituted or unsubstituted C6-C30 aryl group.

[0063] In one exemplary embodiment of the present invention, the triazine phenolic resin may include LA-1356, LA-7052, LA-7054, LA-3018-80P, etc., but is not limited thereto.

[0064] In an exemplary embodiment of the present invention, the total content of the phenolic resin is 5-20 parts by weight, based on the total solids content of 100 parts by weight of the resin composition.

[0065] In an exemplary embodiment of the present invention, the total content of the phenolic resin is 5-15 parts by weight, based on the total solids content of 100 parts by weight of the resin composition.

[0066] When the content of phenolic resin in the resin composition is within the above-mentioned limits, the heat resistance and dielectric properties are improved, and the physical properties required to form appropriate roughness can be ensured in the descaling step.

[0067] In an exemplary embodiment of the present invention, the contents of naphthol-containing phenolic resin and triazine-containing phenolic resin are not particularly limited, as long as the total content range of phenolic resin as defined above is met, and the ratio range of epoxy groups of epoxy resin to hydroxyl groups of phenolic resin as defined above is met.

[0068] In an exemplary embodiment of the present invention, the resin composition may include, based on 100 parts by weight of total phenolic resin, 50-70 parts by weight of naphthol-containing phenolic resin and 30-50 parts by weight of triazine-containing phenolic resin.

[0069] In an exemplary embodiment of the present invention, when the ratio (composition ratio) of the epoxy group of the epoxy resin to the hydroxyl group of the phenolic resin is 1:0.5 to 1:0.01, the resin composition has excellent physical properties of thermal expansion coefficient, while providing appropriate surface roughness through degumming treatment, thereby providing excellent peel strength.

[0070] Based on an epoxy group of epoxy resin, when the number of hydroxyl groups in phenolic resin exceeds 0.5, the resin composition may have an excellent coefficient of thermal expansion, but cannot improve peel strength, thereby causing problems related to substrate blistering and reliability.

[0071] In an exemplary embodiment of the present invention, the ratio of the epoxy group of the epoxy resin to the hydroxyl group of the phenolic resin may be 1:0.5 to 1:0.1, 1:0.5 to 1:0.2, or 1:0.5 to 1:0.3.

[0072] Inorganic filler

[0073] In this disclosure, inorganic fillers refer to fillers used to control the curable resin composition to have desired physical properties, such as suppressing hygroscopicity, high storage modulus, low coefficient of thermal expansion (CTE), viscosity, and improving the curability of the curable resin composition.

[0074] In one exemplary embodiment of the present invention, the average particle size of the inorganic filler may be from 0.01 μm to 5 μm.

[0075] In one exemplary embodiment of the present invention, the inorganic filler may be surface treated with a surface treatment agent, such as a coupling agent.

[0076] In one exemplary embodiment of the present invention, the inorganic filler may include silica, silicates, barium sulfate, alumina, etc., but is not limited thereto.

[0077] In this invention, silicon dioxide can be exemplified as spherical silicon dioxide, molten silicon dioxide, hollow silicon dioxide, crystalline silicon dioxide, amorphous silicon dioxide, etc., but is not limited thereto. Furthermore, silicon dioxide can be commercially obtained from SOC1, SOC2 (Admatechs), etc.

[0078] In one exemplary embodiment of the present invention, the inorganic filler may include silicon dioxide particles.

[0079] In one exemplary embodiment of the present invention, the inorganic filler may consist only of silica particles and exclude any inorganic filler other than silica particles.

[0080] Silica particles may have an average particle size of less than 0.3 μm, less than 0.2 μm, or more than 0.05 μm.

[0081] In an exemplary embodiment of the present invention, the content of inorganic filler may be 60 to 75 parts by weight based on the total solids content of 100 parts by weight of the resin composition.

[0082] In an exemplary embodiment of the present invention, the content of inorganic filler may be 60 to 70 parts by weight based on the total solids content of 100 parts by weight of the resin composition.

[0083] As the content of inorganic filler in the resin composition increases, the coefficient of thermal expansion of the resin composition decreases, which can prevent cracking between the copper wire and the insulation layer. However, when the resin composition includes excessive inorganic filler, there is a problem of difficulty in controlling the viscosity, and the roughened surface has many exposed inorganic filler portions, resulting in a decrease in peel strength.

[0084] When the content of inorganic filler is within the above range, a low coefficient of thermal expansion can be achieved by using inorganic filler, appropriate surface roughness can be achieved by using the composition of epoxy resin and phenolic resin, and excellent peel strength can be provided.

[0085] When the content of inorganic filler is greater than 75 parts by weight, although the coefficient of thermal expansion can be further reduced, sufficient peel strength cannot be obtained. When the content of inorganic filler is less than 60 parts by weight, the coefficient of thermal expansion is too high, leading to reliability problems in thermal cycling tests.

[0086] Thermoplastic resin

[0087] In one exemplary embodiment of the present invention, the resin composition may further comprise a thermoplastic resin to improve the mechanical strength, film-forming properties, etc., of the cured product. The thermoplastic resin is not particularly limited, as long as it is widely known in the art. For example, the thermoplastic resin may include at least one selected from phenolic resins, polyimide resins, polyamide-imide resins, polyether-imide resins, polyurethane resins, polyether ether resins, polyphenylene ether resins, polycarbonate resins, polyether ether ketone resins, polyester resins, and polyvinyl acetal resins. More specifically, the thermoplastic resin includes polyvinyl acetal resin.

[0088] In one exemplary embodiment of the present invention, the thermoplastic resin may be a polyvinyl acetal resin.

[0089] In one exemplary embodiment of the present invention, the total content of the thermoplastic resin is 0.1-5 parts by weight based on the total solids content of 100 parts by weight of the resin composition.

[0090] Curing Accelerator

[0091] In one exemplary embodiment of the present invention, the resin composition may further comprise a curing accelerator.

[0092] When the resin composition contains a curing accelerator, it can effectively cure epoxy resin, phenolic resin, etc. in the resin composition, thereby reducing the curing time.

[0093] In one exemplary embodiment of the present invention, the curing accelerator is not particularly limited, as long as it is a curing accelerator known in the art. For example, the curing accelerator may include at least one selected from phosphorus-based curing accelerators, amine-based curing accelerators, and imidazole-based curing accelerators.

[0094] Phosphorus curing accelerators may include, but are not limited to, triphenylphosphine.

[0095] Amine curing accelerators may include, but are not limited to, triethylamine, tributylamine, 4-dimethylaminopyridine, benzyldimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol, 1,8-diazabicyclo(5.4.0)-undecene, etc.

[0096] Imidazole curing accelerators may include 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole ontyl trimellitate, 1-cyanoethyl-2-phenylimidazole ontyl trimellitate, 2,4-diamino-6-[2'-methylimidazole-] (1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-undecylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-ethyl-4'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine isocyanuric acid adduct, 2-phenylimidazolyl isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazolium, 2-phenyl-4-methyl-5-hydroxymethylimidazolium, 2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazole, 1-dodecyl-2-methyl-3-benzylimidazolyl chloride, 2-methylimidazoline, 2-phenylimidazoline, etc., but not limited to these.

[0097] In an exemplary embodiment of the present invention, based on the total solids content of the resin composition being 100 parts by weight, the content of the curing accelerator may be 0.01-0.5 parts by weight.

[0098] Solvent

[0099] In one exemplary embodiment of the present invention, the resin composition may further comprise a solvent.

[0100] In one exemplary embodiment of the present invention, any solvent may be used without particular limitation, provided that it is a solvent known to those skilled in the art to allow the formation of the resin composition. Non-limiting examples of solvents may include at least one compound selected from the group consisting of esters, ethers, ketones, aromatic hydrocarbons, and argyrites.

[0101] Ester solvents may include ethyl acetate, n-butyl acetate, isobutyl acetate, amyl formate, isoamyl acetate, isobutyl acetate, butyl propionate, isopropyl butyrate, ethyl butyrate, methyl lactate, ethyl lactate, γ-butyrolactone, ε-caprolactone, δ-valerolactone, alkyl oxyacetic esters (e.g., methyl oxyacetate, ethyl oxyacetate, butyl oxyacetate (e.g., methyl methoxyacetate, ethyl methoxyacetate, butyl methoxyacetate, methyl ethoxyacetate, ethyl ethoxyacetate, etc.)), alkyl 3-oxypropionate esters (e.g., methyl 3-oxypropionate, ethyl 3-oxypropionate (e.g., methyl 3-methoxypropionate, ethyl 3-methoxypropionate)). Methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate, etc.), alkyl 2-oxypropionates (e.g., methyl 2-oxypropionate, ethyl 2-oxypropionate, propyl 2-oxypropionate (e.g., methyl 2-methoxypropionate, ethyl 2-methoxypropionate, propyl 2-methoxypropionate, methyl 2-ethoxypropionate, ethyl 2-ethoxypropionate, etc.), methyl 2-oxo-2-methylpropionate and ethyl 2-oxo-2-methylpropionate (e.g., methyl 2-methylpropionate, ethyl 2-ethoxy-2-methylpropionate, etc.), methyl pyruvate, ethyl pyruvate, propyl pyruvate, methyl acetoacetate, ethyl acetoacetate, methyl 2-oxobutyrate, ethyl 2-oxobutyrate, etc.

[0102] Ether solvents may include diethylene glycol dimethyl ether, tetrahydrofuran, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, methyl cellosolve acetate, ethyl cellosolve acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, etc.

[0103] Ketone solvents may include methyl ethyl ketone (MEK), cyclohexanone, cyclopentanone, 2-heptanone, 3-heptanone, N-methyl-2-pyrrolidone, etc.

[0104] Aromatic alkane solvents may include toluene, xylene, anisole, limonene, etc.

[0105] Stone solvents may include dimethyl stone, etc.

[0106] In one exemplary embodiment of the present invention, the resin composition may contain a solvent such that the resin composition has a solids content of 60-80%. When the solids content of the resin composition meets the above range, it may have a suitable viscosity, which may facilitate coating and forming a uniform insulating layer.

[0107] Other Additives

[0108] In one exemplary embodiment of the present invention, the resin composition may further include additives known in the art. Additives may include, but are not limited to, at least one selected from leveling agents, wetting agents, and antistatic agents.

[0109] In one exemplary embodiment of the invention, the leveling agent functions to control the flowability of the curable resin composition during subsequent use to remove defects, such as pits, when subsequently applied to a surface, and includes, but is not limited to, products known in the art, such as BYK350, BYK354, BYK356, BYK 359, BYK399, etc. Optionally, one type of leveling agent may be used alone, or two or more types of leveling agents may be used in combination. Furthermore, the content of the leveling agent may be appropriately varied without departing from the scope of this disclosure.

[0110] In one exemplary embodiment of the present invention, the wetting agent functions to assist the aggregation of the inorganic filler by accelerating wetting, and includes any material known to those skilled in the art, without particular limitation. If necessary, one type of wetting agent may be used alone, or two or more types of wetting agents may be used in combination. Furthermore, the content of the wetting agent may be appropriately varied without departing from the scope of this disclosure.

[0111] In one exemplary embodiment of the present invention, the antistatic agent functions to impart an antistatic effect and includes any material known to those skilled in the art. If necessary, one type of antistatic agent may be used alone, or two or more types of antistatic agents may be used in combination. Furthermore, the content of the antistatic agent may be appropriately varied without departing from the scope of this disclosure.

[0112] In one exemplary embodiment of the present invention, the resin composition may be applied to a printed circuit board. More specifically, the resin composition may be applied to an insulating film of the printed circuit board. The insulating film may be used as an interlayer dielectric material of a multilayer printed circuit board.

[0113] Insulating film

[0114] Another exemplary embodiment of the present invention provides an insulating film comprising the above-described resin composition or a cured thereof.

[0115] In one exemplary embodiment of the present invention, a cured product can be obtained by thermosetting.

[0116] In one exemplary embodiment of the invention, thermosetting can be performed using a heating system under conditions known in the art. Thermosetting can be performed by curing and drying at a temperature of 100°C or higher for a predetermined time.

[0117] In an exemplary embodiment of the present invention, the thickness of the insulating film may be 5 μm or more, 10 μm or more, or 15 μm or more, and 50 μm or less, 40 μm or less, or 35 μm or less.

[0118] In one exemplary embodiment of the present invention, the coefficient of thermal expansion of the insulating film may be below 25 ppm / °C.

[0119] In an exemplary embodiment of the present invention, the lower limit of the coefficient of thermal expansion of the insulating film may be unrestricted, but may be, for example, above 0 ppm / °C.

[0120] The coefficient of thermal expansion is the value measured by a thermomechanical analyzer (TMA) in the range of 25-120°C after the insulating film has been heat-cured at 190°C for 90 minutes.

[0121] An insulating film having a coefficient of thermal expansion that falls within the range defined above subsequently shows a small difference in expansion rate with the support, and therefore does not cause deformation, such as peeling or cracking.

[0122] Conversely, when the coefficient of thermal expansion exceeds 25 ppm / °C, reliability issues may arise during thermal cycling tests.

[0123] According to an exemplary embodiment of the present invention, the insulating film may have a peel strength of 0.4 kgf / cm or higher.

[0124] In one exemplary embodiment of the present invention, the insulating film may have a peel strength of 0.4 kgf / cm or higher, as determined by the method of ASTM D6862.

[0125] When the insulating film has a peel strength of less than 0.4 kgf / cm, blistering and reliability issues may occur in the substrate.

[0126] The peel strength was obtained by copper plating the insulating film as follows, and then measuring the 90° peel strength using a texture analyzer (TA-XTPlus) provided by Stable Micro Systems.

[0127] 1) First copper electroplating treatment (electrochemical copper electroplating)

[0128] The electroplating treatment was performed using Printoganth MV products provided by Atotech, with a coating thickness of 0.5-1.0 μm, and then dried in a hot air oven at 150°C for 30 minutes.

[0129] 2) Second copper electroplating treatment (copper electroplating)

[0130] Electroplating was performed using Expt Inpro SAP6 chemicals provided by Atotech until the coating thickness reached approximately 20 μm, followed by heat treatment at 190°C for 1 hour in a hot air furnace.

[0131] The insulating film according to an exemplary embodiment of the present invention may have a surface roughness (Ra) of 200 to 400 nm or 300 to 400 nm.

[0132] The surface roughness is determined as follows. Using a vacuum press, the insulating film is pressed onto the copper clad laminate (CCL) substrate at 100°C and 0.7 MPa for 30 seconds. Pre-insulation is performed in a hot air furnace at 100°C for 30 minutes, followed by pre-curing at 170°C for 30 minutes. The support film (PET-cured insulating film) of the adhesive layer is then peeled off, allowing the slag-removed insulating film to undergo further treatment. Specifically, a three-step process using Securiganth MV series treatment solution manufactured by Atotech is employed, including expansion solution treatment (60°C, 5 minutes) - oxidation solution treatment (80°C, 20 minutes) - neutralization solution treatment (50°C, 4 minutes). The surface of the insulating layer undergoing the slag removal treatment as described above is determined five times per sample using an optical profilometer (Nanoview 3D Surface Profilometer NV-2700, Nanosystem) (SWI mode, 20X lens), and the average value is taken as the surface roughness (Ra).

[0133] Since the insulating film can be made directly from the above-mentioned resin composition or from its cured form, the description of the resin composition also applies.

[0134] Printed Circuit Board

[0135] Another exemplary embodiment of the present invention provides a printed circuit board comprising the above-described insulating film.

[0136] The printed circuit board may be a multilayer printed circuit board, and the number of layers contained in the multilayer printed circuit board is not limited. For example, the multilayer printed circuit board may include a structure of 2 to 20 layers depending on its purpose and application.

[0137] [Implementing the Invention Model]

[0138] Hereinafter, this disclosure will be described in detail by way of embodiments. However, embodiments of this disclosure may be modified in several different forms, and the scope of this disclosure should not be construed as limited to the embodiments described below. The embodiments of this specification are provided to more fully describe this disclosure to those skilled in the art.

[0139] <Preparation Example 1> Example 1 Preparation of Insulating Film

[0140] First, 22 parts by weight of bisphenol type epoxy resin (YD-128, Guodu Chemical), 66 parts by weight of phenolic varnish type epoxy resin (YDPN-649, Guodu Chemical) and 33 parts by weight of bis(xylenol) type epoxy resin (YX-4000H) were used as epoxy resins, 31 parts by weight of naphthol-containing phenolic resin (SN-485), 22 parts by weight of triazine phenolic resin (LA-1356, DIC), 315 parts by weight of silica slurry (SOC2) with an average particle size of 0.1 μm and 10 parts by weight of polyvinyl alcohol acetal resin (KS-1) were mixed in methyl ethyl ketone (MEK) as solvent until the total solid content was 70%, and stirred at 250 rpm for 3 hours with a mechanical stirrer. Then, 2.5 parts by weight of curing accelerator (DMAP) was mixed with it using a paste mixer to obtain a coating solution.

[0141] The obtained coating solution was coated onto a polyethylene terephthalate (PET) film with a thickness of 38 μm using a coater and dried at 100°C for 8 minutes to obtain an insulating film with a thickness of 30 μm (Example 1).

[0142] In Example 1, the composition ratio of epoxy groups in epoxy resin to hydroxyl groups in phenolic resin is 1:0.48, and the weight ratio of naphthol-containing phenolic resin to triazine-containing phenolic resin is 1.4:1.

[0143] <Preparation Examples 2 and 3 and Comparative Preparation Examples 1-6> Preparation of insulating films of Examples 2 and 3 and Comparative Examples 1-6

[0144] Except for using the composition and content (parts by weight) shown in Table 1 below, the insulating film was obtained in the same manner as in Preparation Example 1.

[0145] [Table 1] type Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Epoxy resin (A) YD-128 twenty two 25 25 18 17 20 18 40 25 YX-4000H 33 38 37 28 26 30 28 60 38 YDPN-639 66 64 62 55 52 60 55 - 64 Phenolic curing agents (B) LA-1356 twenty two 20 twenty one 30 - 65 30 20 20 SN-485 31 27 30 43 80 - - 30 27 GPH-63 - - - - - - 43 - - The composition ratio of epoxy groups (epoxy resin) to hydroxyl groups (phenolic resin) 1:0.48 1:0.4 1:0.45 1:0.8 1:0.8 1:0.8 1:0.8 1:0.48 1:0.4 Inorganic fillers (C) SOC2 315 315 315 315 315 315 315 315 315 thermoplastic resin (D) KS-1 10 10 10 10 10 10 10 10 - Curing accelerator DMAP 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 *GPH-63: Contains biphenyl alkylphenol resin* (based on parts by weight of solids content)

[0146] <Test Example 1>

[0147] The properties of the insulating films of Examples 1-3 and Comparative Examples 1-6 were evaluated. The results are shown in Table 2 below. The properties shown in Table 2 were evaluated as follows.

[0148] Coefficient of thermal expansion (CTE) (ppm / °C)

[0149] The insulating film was cut into samples with a width of 4.8 mm, a length of 16 mm and a thickness of 30 μm. The samples were heat-cured at 190 °C for 90 minutes, and the coefficient of thermal expansion in the range of 25-120 °C was measured using a thermomechanical analyzer (TMA).

[0150] Surface roughness (Ra, nm)

[0151] 1) Degumming treatment

[0152] The insulating film is pressed onto the copper clad laminate (CCL) substrate at a temperature of 100°C and a pressure of 0.7MPa for 30 seconds using a vacuum pressure presser. Then, it is pre-cured in a hot air oven at 100°C for 30 minutes and then pre-cured at 170°C for 30 minutes.

[0153] Then, the support film (PET film) of the insulator is peeled off to expose the insulating layer, and a descaling treatment is performed. The descaling treatment is carried out in three steps using Securiganth MV series treatment solution manufactured by Atotech, including expansion solution treatment (60°C, 5 minutes) - oxidation solution treatment (80°C, 20 minutes) - neutralization solution treatment (50°C, 4 minutes).

[0154] 2) Measurement of surface roughness (Ra, nm)

[0155] The surface of the insulation layer after degumming was measured five times for each sample using an optical profilometer (Nanoview 3D Surface Profilometer NV-2700, Nanosystem) (WSI mode, 20X lens), and the average value was taken as the surface roughness (Ra).

[0156] Peel strength

[0157] 1) Copper plating treatment

[0158] Copper plating was performed using a two-step method involving chemical plating and electroplating. Printoganth MV product manufactured by Atotech was used for chemical plating, with a coating thickness of 0.5–1.0 μm. After treatment, the coating was dried in a hot air furnace at 150°C for 30 minutes.

[0159] Copper was electroplated using Expt Inpro SAP6 chemicals provided by Atotech, with a plating thickness of approximately 20 μm.

[0160] 2) Determination of peel strength (kgf / cm)

[0161] The 90° peel strength of the copper plating was determined using a texture analyzer (TA-XTPlus) provided by Stable Micro Systems.

[0162] [Table 2] coefficient of thermal expansion (CTE, ppm / °C) Surface roughness (Ra, nm) Peel strength (kgf / cm) Example 1 25 300 0.4 Example 2 25 380 0.4 Example 3 twenty four 350 0.4 Comparative Example 1 twenty four 120 0.15 Comparative Example 2 Unable to sample 400 foaming Comparative Example 3 27 500 0.3 Comparative Example 4 29 300 0.2 Comparative Example 5 27 500 0.3 Comparative Example 6 26 400 0.2

[0163] As can be seen from the results in Table 2, the insulating films according to Examples 1 to 3 all meet the coefficient of thermal expansion of 25 ppm / ℃ or lower, while providing a high peel strength of 0.4 kgf / cm or higher, and achieving a suitable surface roughness value of 200-400 nm, thus exhibiting excellent physical properties as insulating films.

[0164] On the other hand, it can be seen that Comparative Example 1 does not meet the above-mentioned range of epoxy groups of epoxy resin and hydroxyl groups of phenolic resin (composition ratio). Therefore, although it has a suitable coefficient of thermal expansion, its surface roughness is low and its peel strength is less than 0.4 kgf / cm, which will cause a short circuit in the subsequent reliability test. Therefore, it is not suitable as an insulating film.

[0165] Furthermore, Comparative Examples 2 and 3 both used only one type of phenolic resin, while Comparative Example 4 used two types of phenolic resin, but used a phenolic resin containing biphenyl aryl groups and a phenolic resin containing triazine (i.e., no phenolic resin containing naphthalene was used). It can be seen that in the case of Comparative Example 2, bubbling occurred, making it unsuitable as an insulating film. It can also be seen that the coefficients of thermal expansion of Comparative Examples 3 and 4 are both higher than 25 ppm / ℃, making it difficult to ensure minimal warpage and potentially leading to low yield. In addition, it can be seen that the peel strength of Comparative Examples 3 and 4 is less than 0.4 kgf / cm, and short circuits occurred in subsequent reliability tests, making them unsuitable as insulating films.

[0166] Finally, it can be seen that Comparative Example 5 used two epoxy resins instead of three, and omitted the use of phenolic varnish-type epoxy resin. Although it meets the above-defined phenolic curing agent composition and the above-defined epoxy group to hydroxyl group composition ratio, its peel strength is still less than 0.4 kgf / cm, and therefore it is not suitable as an insulating film. It can also be seen that Comparative Example 6 does not contain thermoplastic resin, and its peel strength is less than 0.4 kgf / cm, and therefore it is not suitable as an insulating film. [Simplified Explanation of the Diagram]

[0017] None

Claims

1. A resin composition comprising: Epoxy resin; Two or more phenolic resins; Thermoplastic resin; The composition includes inorganic fillers, wherein the ratio of epoxy groups in the epoxy resin to hydroxyl groups in the phenolic resin is 1:0.5 to 1:0.01, the epoxy resin includes bisphenol type epoxy resin, phenolic varnish type epoxy resin, and bis(xylenol) type epoxy resin, the phenolic resin includes naphthol-containing phenolic resin and triazine-containing phenolic resin, and the weight ratio of the naphthol-containing phenolic resin to the triazine-containing phenolic resin is 1:2 to 2:1, wherein based on the total solids content of 100 parts by weight of the resin composition, the content of the inorganic fillers is 60-75 parts by weight, the total content of the epoxy resin is 10-30 parts by weight, the total content of the phenolic resin is 5-20 parts by weight, and the total content of the thermoplastic resin is 0.1-5 parts by weight. Based on a total weight of 100 parts by weight of the epoxy resin, the resin composition may include: 10-30 parts by weight of the bisphenol type epoxy resin, 40-60 parts by weight of the phenolic varnish type epoxy resin, and 20-40 parts by weight of the xylenol type epoxy resin.

2. The resin composition as claimed in claim 1, wherein the thermoplastic resin is a polyvinyl acetal resin.

3. The resin composition as claimed in claim 1 further includes a curing accelerator.

4. An insulating film comprising the resin composition or cured form thereof as described in any one of claims 1 to 3.

5. A printed circuit board comprising the insulating film described in claim 4.