Insulating film and printed circuit board inculindg the same

Abstract

The present specification provides an insulating film comprising: a first layer comprising an inorganic filler surface-treated with an epoxy resin, a cyanate ester resin, and phenylaminosilane; and a second layer comprising an inorganic filler surface-treated with an epoxy resin, a phenolic resin, and epoxysilane, and a printed circuit board comprising the same.

Description

Technology Field

[0001] The present invention relates to an insulating film and a printed circuit board including the same.

[0002] This application claims the benefit of the filing date of Korean Patent Application No. 10-2023-0161738 filed with the Korean Intellectual Property Office on November 21, 2023, the entire contents of which are incorporated herein. Background Technology

[0003] A printed circuit board (PCB) is a support for electronic components, and refers to a board that forms an electronic circuit by fixing electronic components to the surface of the printed circuit board and connecting the components with copper wiring.

[0004] Generally, printed circuit boards are based on forming multiple layers by insulating copper wiring. To increase the reliability of the board, methods have been proposed to improve the adhesion between the insulating layer and the copper foil layer, such as by including a component with high bonding affinity with Cu in the insulating layer or by increasing the surface area of ​​the interface by creating surface roughness on the insulating layer.

[0005] A method for manufacturing multilayer printed circuit boards is known in which a prepreg sheet is laminated onto an inner layer circuit board having copper foil circuits formed thereon, and interlayer connections are made by through-holes; however, this method requires large-scale facilities, consumes a significant amount of time and cost, and has the problem that it is difficult to form fine patterns.

[0006] As a solution to the above problem, a method for manufacturing multilayer printed circuit boards incorporating a build-up approach has recently been proposed. The build-up approach is a technique for alternately laminating a conductor layer and an organic insulating layer (or insulating film) of a circuit board, and includes the steps of vacuum lamination of the insulating film, followed by fore-curing, drilling, shaping, electroless plating, electrolytic plating, post-curing, and outer layer circuit formation.

[0007] In this technical field, there is a demand for insulating films that not only have excellent adhesion to the conductor wiring constituting the conductive layer but also possess excellent chemical resistance, in order to improve the quality of multilayer printed circuit boards.

[0008] In addition, as the demand for low dielectric loss tangents has recently become more sophisticated, there is also a demand for insulating films that possess high heat resistance and low dielectric properties. Prior art literature

[0009] Korean Patent Publication No. 2012-0107277 The problem to be solved

[0010] The present invention aims to provide an insulating film and a printed circuit board including the same. means of solving the problem

[0011] One embodiment of the present specification comprises a first layer comprising an epoxy resin, a cyanate ester resin, and an inorganic filler surface-treated with phenylaminosilane; and

[0012] An insulating film is provided comprising a second layer comprising an inorganic filler surface-treated with an epoxy resin, a phenolic resin, and an epoxy silane.

[0013] Another embodiment of the present specification provides a printed circuit board comprising the insulating film. Effects of the invention

[0014] The insulating film according to the present specification has a low coefficient of linear thermal expansion, which can prevent cracking in future reliability tests of the insulating film.

[0015] In addition, the insulating film according to the present specification exhibits low surface roughness and excellent plating adhesion.

[0016] In addition, the insulating film according to the present specification exhibits excellent dielectric properties. Specific details for implementing the invention

[0017] The present specification will be described in more detail below.

[0018] In this specification, when it is said that a member is located "on" another member, this includes not only cases where a member is in contact with another member, but also cases where another member exists between the two members.

[0019] In this specification, when a part is described as "comprising" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components.

[0020] A method for manufacturing multilayer printed circuit boards by alternately laminating conductor layers and insulating films has been developed and is currently used for semiconductor packaging. The manufacturing process of the aforementioned multilayer printed circuit board involves first vacuum laminating a build-up insulating film onto the inner layer circuits, followed by the sequence of pre-curing → drilling → surface roughening → electroless plating → electrolytic plating → post-curing → outer layer circuit formation. In this process, the surface roughening step utilizes an acidic solution to remove smear while simultaneously eroding the surface of the insulating film to a certain degree to create surface roughness; this serves to enhance adhesion with the copper foil layer formed in subsequent processes.

[0021] In terms of the adhesion between the copper foil layer and the insulating layer, a high surface roughness after the coating process is advantageous; however, if the surface roughness is excessively high, it is unsuitable because it prolongs the time required to remove the electroless plating. Therefore, there is a need to develop an insulating film that possesses low surface roughness while maintaining high plating adhesion.

[0022] Conventionally, for the manufacture of build-up insulating films, a composition in which silica particles were filled into an epoxy resin and a phenolic curing agent was used. However, as the demand for low dielectric properties and low CTE (coefficient of thermal expansion) increased, a product using a cyanate ester-based curing agent in an epoxy resin was developed.

[0023] However, when the cured product of the above epoxy resin and cyanate ester-based curing agent is used alone, there was a problem in that the desired surface roughness could not be formed through the harmonization treatment process.

[0024] Accordingly, the present specification aims to provide an insulating film that exhibits not only low CTE characteristics but also desired surface roughness and high plating adhesion, and a printed circuit board including the same.

[0025] One embodiment of the present specification provides an insulating film comprising: a first layer comprising an inorganic filler surface-treated with an epoxy resin, a cyanate ester resin, and phenylaminosilane; and a second layer comprising an inorganic filler surface-treated with an epoxy resin, a phenolic resin, and epoxysilane.

[0026] In one embodiment of the present specification, it is preferable that the epoxy resin has two or more epoxy groups within one molecule. Specifically, the epoxy resin may include one or more selected from bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, naphthalene type epoxy resin, anthracene epoxy resin, biphenyl type epoxy resin, tetramethyl biphenyl type epoxy resin, phenol novolak type epoxy resin, cresol novolak type epoxy resin, bisphenol A novolak type epoxy resin, bisphenol S novolak type epoxy resin, biphenyl novolak type epoxy resin, naphthol novolak type epoxy resin, naphthol phenol coaxial novolak type epoxy resin, naphthol coresol coaxial novolak type epoxy resin, aromatic hydrocarbon formaldehyde resin modified phenol resin type epoxy resin, triphenyl methane type epoxy resin, tetraphenylethane type epoxy resin, dicyclopentadiene phenol addition reaction type epoxy resin, phenol aralkyl type epoxy resin, and naphthol aralkyl type epoxy resin, but is not limited thereto.

[0027] Among these, in terms of heat resistance, insulation reliability, and adhesion, it is more preferable that the epoxy resin includes one or more types, such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, naphthalene type epoxy resin, and biphenyl type epoxy resin.

[0028] In one embodiment of the present specification, the first layer and the second layer include an epoxy resin, thereby improving plating adhesion and enhancing the flexibility of the insulating film, which in turn improves brittleness.

[0029] In one embodiment of the present specification, the cyanate ester resin may include one or more selected from novolak-type (phenol novolak-type, alkylphenol novolak-type, etc.) cyanate ester resin, dicyclopentadiene-type cyanate ester resin, bisphenol-type (bisphenol A-type, bisphenol F-type, bisphenol S-type, bisphenol M-type, etc.) cyanate ester resin and prepolymers partially triazinated therefrom, but is not limited thereto.

[0030] Specifically, the cyanate ester-based resin comprises difunctional cyanate resins such as bisphenol A dicyanate, polyphenol cyanate, oligo(3-methylene-1,5-phenylenecyanate), 4,4'-methylenebis(2,6-dimethylphenylcyanate), 4,4'-ethylidene diphenyl dicyanate, hexafluorobisphenol A dicyanate, 2,2-bis(4-cyanate)phenylpropane, 1,1-bis(4-cyanatephenylmethane), bis(4-cyanate-3,5-dimethylphenyl)methane, 1,3-bis(4-cyanatephenyl-1-(methylethylidene))benzene, bis(4-cyanatephenyl)thioether, bis(4-cyanatephenyl)ether, etc.; and polyfunctional cyanate resins derived from phenol novolac, cresol novolac, dicyclopentadiene structure-containing phenol resins, etc. and these cyanate resins may include one or more selected from some triazinated prepolymers.

[0031] The weight average molecular weight of the above cyanate ester resin may be 500 g / mol to 4,500 g / mol and 600 g / mol to 3,000 g / mol, but is not limited thereto.

[0032] In one embodiment of the present specification, the weight average molecular weight may be measured by gel permeation chromatography (GPC) (polystyrene equivalent).

[0033] In one embodiment of the present specification, the insulating film exhibits the effect of exhibiting a low dielectric loss tangent by including a cyanate ester-based resin only in the first layer. Specifically, when a phenol resin is included, the dielectric loss tangent is 0.013 to 0.015 at 10 GHz, whereas the insulating film according to one embodiment of the present specification exhibits the effect of exhibiting a low dielectric loss tangent of 0.001 to 0.006 at 10 GHz by including a cyanate ester-based resin in the first layer.

[0034] In one embodiment of the present specification, the phenolic resin is a compound comprising a phenolic skeleton or a naphthol skeleton, and may include one or more selected from biphenyl-type phenolic resins and novolak-type phenolic resins having excellent heat resistance, water resistance, etc. Specifically, the phenolic resin may be a novolak-type phenolic resin. More specifically, the phenolic resin may include one or more selected from biphenylaralkyl-type phenolic resin, phenol novolak resin, bisphenol A novolak resin, cresol novolak resin, phenol-modified xylene resin, alkyl phenolic resin, and phenol-modified melamine resin.

[0035] In one embodiment of the present specification, the insulating film includes a phenolic resin only in the second layer, thereby forming an appropriate roughness during the shaping treatment step and exhibiting the effect of improving polarity and plating adhesion.

[0036] In one embodiment of the present specification, the inorganic filler comprises silica particles.

[0037] In one embodiment of the present specification, the inorganic filler comprises only silica particles and does not include any other inorganic filler in addition to the silica particles.

[0038] In one embodiment of the present specification, the silica may be spherical silica, fused silica, hollow silica, crystalline silica, amorphous silica, etc., but is not limited thereto.

[0039] In one embodiment of the present specification, the average particle size of the silica particles may be 0.3 μm or less, 0.2 μm or less, and 0.05 μm or more.

[0040] In one embodiment of the present specification, SOC1, SOC2 (Admatex), etc. are commercially available as the inorganic filler.

[0041] In one embodiment of the present specification, the inorganic filler is a surface-treated inorganic filler with phenylaminosilane or a surface-treated inorganic filler with epoxysilane. Specifically, a surface-treated inorganic filler with phenylaminosilane is used in the first layer of the insulating film, and a surface-treated inorganic filler with epoxysilane is used in the second layer.

[0042] Generally, when the resin composition of the surface layer is etched to a certain thickness by wet roughening treatment, a shape in which the inorganic filler portion protrudes or a shape in which the inorganic filler detaches is formed, and in this case, the type of inorganic filler becomes an important factor in determining the surface roughness. When an untreated inorganic filler (silica) is used, even if the resin composition is etched well, there is a problem in that the adhesion is reduced because the surface roughness is too high. On the other hand, according to one embodiment of the present specification, by applying the aforementioned inorganic filler to the first layer and the second layer, respectively, a desired surface roughness can be formed by roughening treatment.

[0043] Specifically, as in one embodiment of the present specification, when the first layer and the second layer each contain inorganic fillers surface-treated with different materials, the etching rates for the harmonizing treatment solution are different, and as a result, non-uniform etching of the surface layer is induced during the harmonizing treatment process, thereby allowing the formation of a desired surface roughness.

[0044] In one embodiment of the present specification, the surface-treated inorganic filler may be an epoxy silane surface-treated product (Admatex SC-2050-MB), a phenylamino silane surface-treated product (Admatex SC-2050-MTO), etc., but is not limited thereto.

[0045] In one embodiment of the present specification, the first layer and the second layer may each further include a thermoplastic resin to improve mechanical strength, film forming performance, etc. The thermoplastic resin may include one or more selected from phenoxy resin, polyimide resin, polyamideimide resin, polyetherimide resin, polysulfone resin, polyethersulfone resin, polyphenylene ether resin, polycarbonate resin, polyetheretherketone resin, polyester resin, polyvinyl acetal resin, and polyvinyl butyral resin. It is more preferable that the thermoplastic resin includes phenoxy resin.

[0046] In one embodiment of the present specification, the first layer and the second layer may each further comprise one or more thermoplastic resins selected from phenoxy resin, polyimide resin, polyamideimide resin, polyetherimide resin, polysulfone resin, polyethersulfone resin, polyphenylene ether resin, polycarbonate resin, polyetheretherketone resin, polyester resin, polyvinyl acetal resin, and polyvinyl butyral resin.

[0047] In one embodiment of the present specification, the weight average molecular weight of the thermoplastic resin may be 5,000 g / mol to 200,000 g / mol, but is not limited thereto.

[0048] In one embodiment of the present specification, the first layer and the second layer may include a thermoplastic resin so as to maintain a film shape during the curing stage. Specifically, when a thermoplastic resin is not included, the viscosity decreases upon heating, causing the material to flow down, whereas in one embodiment of the present specification, the viscosity is maintained or improved by including a thermosetting resin so as to maintain a film shape even during the curing stage.

[0049] In one embodiment of the present specification, the first layer and the second layer each further comprise an additive, and the additive is one or more selected from a curing accelerator, a leveling agent, a wetting agent, an antistatic agent, a flame retardant, a crosslinking agent, a curing agent, and a polymerization initiator.

[0050] In one embodiment of the present specification, the curing accelerator is a substance that shortens the curing time and is known in the art, such as a phosphorus-based curing accelerator, an amine-based curing accelerator, an imidazole-based curing accelerator, etc. If necessary, one type of curing accelerator may be used alone or two or more types may be used in combination, and the content thereof may be appropriately changed as long as it does not deviate from the scope of the present invention.

[0051] The above-mentioned phosphorus-based curing accelerators include triphenylphosphine, and amine-based curing accelerators include triemylamine, tributylamine, etc., but are not particularly limited.

[0052] The above imidazole-based promoters 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-undecylimidazolium trimellitate, 1-Cyanoethyl-2-phenylimidazolium trimellitate, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-undecylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-ethyl-4'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine isocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, It may include one or more selected from 2,3-dihydro-1H-pyrrol[1,2-a]benzimidazole, 1-dodecyl-2-methyl-3-benzylimidazolium chloride, 2-methylimidazoline, and 2-phenylimidazoline.

[0053] The above curing accelerator may additionally include one or more selected from metal-based compounds, amine-based compounds, and organic phosphine-based compounds.

[0054] Examples of the above metal compounds include organometallic complexes or organometallic salts of metals such as cobalt, copper, zinc, iron, nickel, manganese, and tin. Examples of the above organometallic complexes include cobalt (II) acetylacetonate, cobalt (III) acetylacetonate, copper (II) acetylacetonate, zinc (II) acetylacetonate, iron (III) acetylacetonate, nickel (II) acetylacetonate, and manganese (II) acetylacetonate, but are not limited thereto. Additionally, examples of the above organometallic salts include zinc octylate, tin octylate, zinc naphthenate, cobalt naphthenate, tin stearate, and zinc stearate, but are not limited thereto.

[0055] The above amine compounds include triethylamine, tributylamine, 4-dimethylaminopyridine, benzyldimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol and 1,8-diazabicyclo(5,4,0)-undecene, but are not limited thereto.

[0056] In one embodiment of the present specification, the leveling agent controls the flowability when the curable resin composition is used in the future, thereby preventing defects such as craters when applied to a surface in the future. Examples of such agents known in the industry include BYK 350, BYK 354, BYK 356, BYK 359, and BYK 399, but are not particularly limited. In some cases, one or more of the leveling agents may be used in combination, and their content may be appropriately changed without departing from the scope of the present invention.

[0057] In one embodiment of this specification, the wetting agent is a substance that accelerates wetting to aid in the aggregation of the inorganic filler, and is not particularly limited to substances known in the art. If necessary, one type of wetting agent may be used alone or in combination of two or more types, and the content thereof may be appropriately changed without departing from the scope of the present invention.

[0058] In one embodiment of the present specification, the antistatic agent is a substance that imparts an antistatic effect and is not particularly limited to those known in the art. If necessary, one type of antistatic agent may be used alone or two or more types may be used in combination, and the content thereof may be appropriately changed as long as it does not deviate from the scope of the present invention.

[0059] In one embodiment of the present specification, the flame retardant is a substance that reduces flammability or delays combustion, and is not particularly limited to those known in the art. If necessary, one type of flame retardant may be used alone or in combination of two or more types, and the content thereof may be appropriately changed as long as it does not deviate from the scope of the present invention.

[0060] In one embodiment of the present specification, the crosslinking agent is a material that forms crosslinking bonds between polymers, and is known in the art as TAIC, DAIC (allyl-based), ALP-d (benxoxazine-based), etc., but is not particularly limited. If necessary, one type of crosslinking agent may be used alone or two or more types may be used in combination, and the content thereof may be appropriately changed as long as it does not depart from the scope of the present invention.

[0061] In one embodiment of the present specification, the curing agent is a substance added to a curable resin to assist in the curing reaction, and is known in the art and may be classified as active ester-based curing agents, phenol-based curing agents, cyanate ester-based curing agents, etc., but is not particularly limited. If necessary, one type of curing agent may be used alone or two or more types may be used in combination, and the content thereof may be appropriately changed as long as it does not deviate from the scope of the present invention.

[0062] In one embodiment of the present specification, the polymerization initiator is a substance that initiates polymerization by generating radicals or (cations) upon a specific stimulus, and is known in the art, such as dicumyl peroxide, t-butylcumyl peroxide, di-t-butyl peroxide, etc., but is not particularly limited. If necessary, one type of polymerization initiator may be used alone or two or more types may be used in combination, and the content thereof may be appropriately changed as long as it does not deviate from the scope of the present invention.

[0063] In one embodiment of the present specification, the weight ratio of the inorganic filler to the resin of the first layer is 80:20 to 40:60.

[0064] At this time, the resin described in the content ratio of the first layer is the sum of the weights of all resins included in the first layer. For example, if the first layer includes an epoxy resin, a cyanate ester resin, and a phenoxy resin, the resin is the sum of the total weights of the epoxy resin, the cyanate ester resin, and the phenoxy resin.

[0065] In one embodiment of the present specification, the weight ratio of the inorganic filler to the resin of the second layer is 80:20 to 40:60.

[0066] At this time, the resin described in the content ratio of the second layer is the sum of the weights of all resins included in the second layer. For example, if the second layer includes epoxy resin, phenolic resin, and phenoxy resin, the resin is the sum of the total weights of the epoxy resin, phenolic resin, and phenoxy resin.

[0067] If the content of the above-mentioned inorganic filler is less than 40 weight% or more than 80%, it may be difficult to achieve the desired surface shape through the harmonization process, so it is not desirable.

[0068] In one embodiment of the present specification, the thickness of the first layer is 15 μm to 25 μm. When the above range is satisfied, it has the effect of exhibiting appropriate dielectric properties and CTE properties.

[0069] In one embodiment of the present specification, the thickness of the second layer is 1 μm to 5 μm. If the thickness of the second layer is less than 1 μm, it is completely etched during the shaping process and cannot exhibit the desired adhesion, and if the thickness of the second layer exceeds 5 μm, there is a problem in that it cannot exhibit appropriate dielectric properties and CTE properties.

[0070] In one embodiment of the present specification, the insulating film has a coefficient of thermal expansion value of 25 ppm / ℃ or less when measured in the range of 25℃ to 120℃. Specifically, the coefficient of thermal expansion value is 24 ppm / ℃ or less, or 22 ppm / ℃ or less, and 0 ppm / ℃ or more.

[0071] The above coefficient of thermal expansion is a value measured in the range of 25°C to 120°C using a TMA (thermos mechanical analyzer) after heat-curing the insulating film at 190°C for 90 minutes.

[0072] Insulating films falling within the range of the coefficient of thermal expansion mentioned above do not exhibit deformations such as delamination or cracking because there is almost no difference in expansion rate with the support in the future.

[0073] In one embodiment of the present specification, the insulating film has a dielectric dissipation factor (Df) of 0.001 or more and 0.006 or less, measured at 10 GHz according to ASTM D2520. Specifically, the dielectric dissipation factor may be 0.0011 or more, 0.0012 or more, or 0.0013 or more, and 0.0058 or less, 0.0055 or less, or 0.0052 or less.

[0074] An insulating film having a dielectric loss tangent as described above can minimize future transmission signal loss.

[0075] In one embodiment of the present specification, the insulating film has an adhesion force greater than 0.5 kgf / cm as measured according to ASTM D6862. Specifically, the adhesion force is 0.52 kgf / cm or more or 0.55 kgf / cm or more, and 2 kgf / cm or less or 1.8 kgf / cm or less.

[0076] In one embodiment of the present specification, a first insulating film composition and a second insulating film composition are used to form the first layer and the second layer.

[0077] In one embodiment of the present specification, the composition for the first insulating film comprises an epoxy resin, a cyanate ester resin, and an inorganic filler surface-treated with phenylaminosilane.

[0078] In one embodiment of the present specification, the composition for the second insulating film comprises an epoxy resin, a phenolic resin, and an inorganic filler surface-treated with an epoxy silane.

[0079] In one embodiment of the present specification, the first insulating film composition and the second insulating film composition further comprise a thermoplastic resin.

[0080] In one embodiment of the present specification, the first insulating film composition and the second insulating film composition further comprise an additive.

[0081] In one embodiment of the present specification, the materials such as epoxy resin, cyanate ester resin, phenolic resin, inorganic filler, thermoplastic resin, and additive included in the first insulating film composition and the second insulating film composition are each as described above in the insulating film.

[0082] In one embodiment of the present specification, the first insulating film composition and the second insulating film composition further comprise a solvent. The solvent may be applied without particular limitation as long as it is known in the art to which the present invention belongs to to enable the formation of an insulating film. As a non-limiting example, the solvent may be one or more compounds selected from the group consisting of esters, ethers, ketones, aromatic hydrocarbons, and sulfoxides.

[0083] The above ester solvents are ethyl acetate, n-butyl acetate, isobutyl acetate, amyl formate, isoamyl acetate, isobutyl acetate, butyl propionate, isopropyl butyrate, ethyl butyrate, butyl butyrate, methyl lactate, ethyl lactate, gamma-butyrolactone, epsilon-caprolactone, delta-valerolactone, alkyl oxyacetates (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, etc. (e.g., 3-methyl methoxypropionate, 3-ethyl methoxypropionate, 3-methyl ethoxypropionate, 3-ethyl ethoxypropionate, etc.), 2-alkyl esters of oxypropionate (e.g., methyl 2-oxypropionate, ethyl 2-oxypropionate, propyl 2-oxypropionate, etc. (e.g., methyl methoxypropionate, ethyl 2-methoxypropionate, propyl methoxypropionate, 2-methyl ethoxypropionate, ethyl 2-ethoxypropionate)), 2-methyl-2-methylpropionate and 2-ethyl-2-methylpropionate (e.g., methyl-2-methylpropionate, ethyl-2-ethoxypropionate, etc.), methyl pyruvate, It may be ethyl pyruvate, propyl pyruvate, methyl acetoacetate, ethyl acetoacetate, 2-methyl oxobutanate, 2-ethyl oxobutanate, etc.

[0084] The above ether solvents may be 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.

[0085] The above ketone solvents may be methyl ethyl ketone (MEK), cyclohexanone, cyclopentanone, 2-heptanone, 3-heptanone, N-methyl-2-pyrrolidone, etc.

[0086] The above aromatic hydrocarbon solvents may be toluene, xylene, anisole, limonene, etc.

[0087] The above sulfoxide solvent may be dimethyl sulfoxide, etc.

[0088] One embodiment of the present specification provides a printed circuit board comprising the insulating film described above.

[0089] In one embodiment of the present specification, the insulating film comprises a substrate film, and the insulating film is provided in which the substrate film, the first layer, and the second layer are sequentially laminated. When the above lamination order is satisfied, it has the effect of exhibiting appropriate dielectric properties and CTE properties.

[0090] On the other hand, when the above-mentioned film, the above-mentioned second layer, and the above-mentioned first layer are stacked sequentially, there is a problem in that the surface roughness is high and the adhesion is low.

[0091] In one embodiment of the present specification, the insulating film may be applied as an insulating layer of a printed circuit board. Additionally, the insulating film may be used as an interlayer insulating material of a multilayer printed circuit board.

[0092] In one embodiment of the present specification, the insulating film may be used as a build-up insulating layer for manufacturing a predetermined circuit board. For example, the insulating film may be for manufacturing an interlayer insulating layer constituting various types of package boards, including flexible printed circuit boards (flexible PCBs), rigid printed circuit boards (rigid PCBs), rigid-flexible printed circuit boards (RF PCBs), and build-up printed circuit boards.

[0093] In one embodiment of the present specification, the printed circuit board may be a multilayer printed circuit board, and the number of layers included in the multilayer printed circuit board is not limited. For example, depending on the purpose of use, application, etc. of the multilayer printed circuit board, the multilayer printed circuit board may include a structure of 2 to 20 layers.

[0094] Hereinafter, to specifically explain this specification, examples will be described in detail. However, the embodiments according to this specification may be modified in various different forms, and the scope of this specification is not to be interpreted as being limited to the embodiments described below. The embodiments of this specification are provided to more completely explain this specification to those with average knowledge in the art.

[0096] <Example>

[0097] Example 1.

[0098] 5 parts by weight of bisphenol A type epoxy resin (YD-128, Kukdo Chemical), 3 parts by weight of bisphenol F type epoxy resin (KDS-8170), 2 parts by weight of naphthalene type epoxy resin (HP-4032D, DIC), 5 parts by weight of biphenyl type epoxy resin (YX4000UH, Mitsubishi Chemical), 20 parts by weight of cyanate ester resin (LMP-500S, Arsada), 10 parts by weight of phenoxy resin (YX6954BH30, Mitsubishi Chemical), 100 parts by weight of spherical silica surface-treated with phenylaminosilane (average particle diameter 0.5㎛, SOC2, Admatex), and 1 part by weight of imidazole-based curing accelerator (2PHZ-PW) were mixed in MEK solvent to a total solid content concentration of 70%, and then stirred with a stirrer at 250 rpm for 3 hours to obtain resin mixture 1. Manufactured.

[0099] 5 parts by weight of bisphenol A type epoxy resin (YD-128, Kukdo Chemical), 2 parts by weight of naphthalene type epoxy resin (HP-4032D, DIC), 10 parts by weight of biphenyl type epoxy resin (YX4000UH, Mitsubishi Chemical), 25 parts by weight of biphenylaralkyl type phenol resin (GPH 103, Nippon Explosives), 20 parts by weight of phenoxy resin (YX6954BH30, Mitsubishi Chemical), 100 parts by weight of spherical silica surface-treated with epoxy silane (average particle diameter 0.5㎛, SOC2, Admatex), and 1 part by weight of imidazole-based curing accelerator (2PHZ-PW) were mixed in MEK solvent to a total solid content concentration of 60%, and then stirred with a stirrer at 250 rpm for 3 hours to prepare resin mixture 2.

[0100] A first layer was prepared by uniformly coating a prepared resin mixture 1 onto a 40㎛ PET film to a thickness of 20㎛ and drying it at 100℃ for 5 minutes. A second layer was prepared by uniformly coating a prepared resin mixture 2 onto the first layer to a thickness of 5㎛ and drying it at 100℃ for 8 minutes, thereby producing an insulating film with a total thickness of 25㎛ from the first and second layers.

[0102] Example 2.

[0103] An insulating film was prepared in the same manner as in Example 1, except that resin mixture 1 was uniformly applied to a thickness of 19 μm and resin mixture 2 to a thickness of 6 μm.

[0105] Comparative Example 1.

[0106] A resin mixture 1 prepared in Example 1 was uniformly applied onto a 40㎛ PET film and then dried at 100℃ for 5 minutes to produce an insulating film with a thickness of 25㎛.

[0108] Comparative Example 2.

[0109] A resin mixture 2 prepared in Example 1 was uniformly coated onto a 40㎛ PET film and then dried at 100℃ for 5 minutes to produce an insulating film with a thickness of 25㎛.

[0111] Comparative Example 3.

[0112] An insulating film was prepared in the same manner as in Example 1, except that spherical silica surface-treated with phenylaminosilane was used instead of spherical silica surface-treated with epoxysilane when preparing resin mixture 2 in Example 1.

[0114] Comparative Example 4.

[0115] An insulating film was prepared in the same manner as in Example 1, except that spherical silica surface-treated with epoxy silane was used instead of spherical silica surface-treated with phenylamino silane when preparing resin mixture 1 in Example 1.

[0117] Comparative Example 5.

[0118] An insulating film was manufactured in the same manner as in Example 1, except that the resin mixture 2 prepared in Example 1 was uniformly applied to a thickness of 5 μm on a 40 μm PET film and dried at 100°C for 5 minutes to produce a first layer, and the resin mixture 1 prepared thereon was uniformly applied to a thickness of 20 μm and dried at 100°C for 8 minutes to produce a second layer, thereby producing an insulating film with a total thickness of 25 μm of the first and second layers.

[0120] <Experimental Example>

[0121] The characteristics of the insulating films prepared in the above examples and comparative examples were evaluated and are shown in Table 1 below. The evaluation methods for the characteristics listed in Table 1 below are as follows.

[0123] Experimental Example 1. Measurement of Permittivity and Dielectric Loss Tangent

[0124] The insulating film prepared in the above examples and comparative examples was heat-cured by heating at 190°C for 90 minutes, and the PET film serving as a support was peeled off to obtain a cured product.

[0125] For the cured material, the Agilent E5071C instrument was used to measure the dielectric constant and dielectric loss tangent at 10 GHz under conditions of a measurement temperature of 20–25°C and a humidity of 50% or less. The measurement results are as shown in Table 1 below.

[0127] Experimental Example 2. Measurement of Coefficient of Thermal Expansion (CTE)

[0128] After heat-curing the insulating film at 190°C for 90 minutes, the coefficient of thermal expansion in the range of 25°C to 120°C was measured using a TMA (thermos mechanical analyzer). The measurement results are as shown in Table 1 below.

[0130] Experimental Example 3. Measurement of Surface Roughness (Ra, nm) and Adhesion

[0131] 1) Laminate

[0132] The insulating films prepared in the above examples and comparative examples were laminated onto a copper substrate that had undergone a harmonization treatment using a vacuum pressure laminator.

[0133] 2) Curing

[0134] An insulating film laminated on a copper substrate was precured in a hot air oven at 100°C for 30 minutes, followed by 180°C for 30 minutes, to obtain an insulating layer.

[0135] 3) Harmonic treatment

[0136] The heat-cured substrate was treated with a swelling solution (Swelling Deep Securigant P, Atotech) at 80°C for 5 minutes, an oxidation solution (Concentrate Compact P, Atotech) at 75°C for 20 minutes, and a neutralization solution (Reduction Solution Securigant P, Atotech) at 50°C for 20 minutes.

[0137] 4) Plating

[0138] After forming a plating layer with a thickness of 30㎛ on the substrate that had undergone the treatment, it was heat-treated at 190℃ for 60 minutes.

[0139] 5) Measurement of surface roughness (Ra, nm)

[0140] Surface roughness (Ra) was calculated by measuring the insulating film treated with a shaping process five times per sample using an Optical Profiler (Nanoview 3D surface profiler NV-2700, Nanosystem) (WSI mode, 20x lens) and taking the average value. The measurement results are as shown in Table 1 below.

[0141] 6) Adhesion measurement

[0142] The adhesion between the plating layer and the insulating layer of the plated insulating film was measured according to ASTM D6862. The measurement results are as shown in Table 1 below.

[0144] permittivity genetic correction Coefficient of Thermal Expansion (CTE) Surface roughness (Ra) Adhesion (ppm / ℃) (nm) (kgf / cm) Example 1 3.2 0.005 22 200 0.7 Example 2 3.1 0.006 25 200 0.6 Comparative Example 1 3.0 0.005 20 900 0.5 Comparative Example 2 3.2 0.013 39 200 0.5 Comparative Example 3 3.2 0.007 27 400 0.2 Comparative Example 4 3.2 0.007 29 200 0.5 Comparative Example 5 3.2 0.005 22 900 0.4

[0145] As shown in the above results, Example 1 exhibited low surface roughness and coefficient of thermal expansion, while exhibiting excellent dielectric constant and adhesion.

[0146] In Example 2, the insulating film includes a first layer and a second layer and exhibits low surface roughness, but the thickness of the second layer exceeds 5 μm, and it was confirmed that the coefficient of thermal expansion and dielectric loss tangent were significantly higher compared to Example 1.

[0147] However, in the case of Comparative Example 1, in which the insulating film consisted only of the first layer, a large surface roughness was exhibited, and in the case of Comparative Example 2, in which the insulating film consisted only of the second layer, a large coefficient of thermal expansion was observed.

[0148] In addition, in Comparative Example 3, where the inorganic filler constituting the first and second layers is the same (identical to the inorganic filler surface-treated with phenylaminosilane), both the coefficient of thermal expansion and surface roughness were large and the adhesion was low, and in Comparative Example 4, where the inorganic filler surface-treated with epoxysilane was the same, the coefficient of thermal expansion was large.

[0149] Furthermore, in the case of Comparative Example 5, in which the stacking order of the first and second layers is reversed compared to the example, the surface roughness was high and the adhesion was low.

[0150] Through this, it can be confirmed that the insulating film according to one embodiment of the present specification has appropriate surface roughness and a coefficient of thermal expansion, while simultaneously having excellent adhesion and dielectric constant.

[0151] Accordingly, a multilayer printed circuit board with excellent wiring adhesion, chemical resistance, etc. can be manufactured using an insulating film according to one embodiment of the present specification.

Claims

Claim 1 An insulating film comprising: a first layer comprising an inorganic filler surface-treated with an epoxy resin, a cyanate ester resin, and a phenylamino silane; a second layer comprising an inorganic filler surface-treated with an epoxy resin, a phenolic resin, and an epoxy silane; and a substrate film, wherein the substrate film, the first layer, and the second layer are sequentially laminated. Claim 2 An insulating film according to claim 1, wherein the thickness of the first layer is 15㎛ to 25㎛. Claim 3 An insulating film according to claim 1, wherein the thickness of the second layer is 1 μm to 5 μm. Claim 4 An insulating film according to claim 1, wherein the cyanate ester resin comprises one or more selected from novolak-type cyanate ester resin, dicyclopentadiene-type cyanate ester resin, bisphenol-type cyanate ester resin, and prepolymers partially triazinated therefrom. Claim 5 An insulating film according to claim 1, wherein the phenolic resin comprises one or more types selected from biphenyl-type phenolic resins and novolak-type phenolic resins. Claim 6 An insulating film according to claim 1, wherein the first layer and the second layer each further comprise one or more thermoplastic resins selected from phenoxy resin, polyimide resin, polyamideimide resin, polyetherimide resin, polysulfone resin, polyethersulfone resin, polyphenylene ether resin, polycarbonate resin, polyetheretherketone resin, polyester resin, polyvinyl acetal resin, and polyvinyl butyral resin. Claim 7 An insulating film according to claim 1, wherein the first layer and the second layer each further comprise an additive, and the additive is one or more selected from a curing accelerator, a leveling agent, a wetting agent, an antistatic agent, a flame retardant, a crosslinking agent, a curing agent, and a polymerization initiator. Claim 8 delete Claim 9 The insulating film of claim 1, wherein the insulating film has a coefficient of thermal expansion value of 25 ppm / ℃ or less measured in the range of 25℃ to 120℃. Claim 10 The insulating film of claim 1, wherein the insulating film has a dielectric loss tangent of 0.001 or more and 0.006 or less as measured at 10 GHz according to ASTM D2520. Claim 11 The insulating film of claim 1, wherein the insulating film has an adhesion force greater than 0.5 kgf / cm as measured according to ASTM D6862. Claim 12 A printed circuit board comprising an insulating film according to any one of claims 1 to 7 and 9 to 11.

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