Thermosetting resin composition, and insulating film and printed circuit board comprising same

Abstract

The present specification relates to a thermosetting resin composition, and an insulating film and a printed circuit board comprising the same, the thermosetting resin composition comprising an epoxy resin as a curable resin, a cyanate ester resin and a phenol resin as curing agents, and silica having an average particle diameter of 0.1 [mu] m or more and less than 0.2 [mu] m as an inorganic filler. The thermosetting resin composition according to an exemplary embodiment can ensure excellent curing characteristics and excellent high temperature reliability.

Description

Technical Field

[0001] This specification relates to thermosetting resin compositions and insulating films and printed circuit boards containing the same.

[0002] This application claims priority and benefit to Korean Patent Application Nos. 10-2023-0171426 and 10-2024-0143082, filed with the Korean Intellectual Property Office on November 30, 2023 and October 18, 2024, respectively, the entire contents of which are incorporated herein by reference. Background Technology

[0003] A printed circuit board (PCB) is a board that serves as a support for electronic components, in which the electronic components are fixed to the surface of the printed circuit board and the components are connected by copper wiring to form an electronic circuit.

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

[0005] As a method for manufacturing multilayer printed circuit boards, it is known that layers are stacked on an inner circuit board on which copper foil circuits are formed using prepreg sheets, and interlayer connections are made through vias. However, this method requires large-scale installation, is extremely expensive and time-consuming, and has the problem of difficulty in forming fine patterns.

[0006] As a solution to the above problems, a method for manufacturing multilayer printed circuit boards in combination with the stacking method has recently been proposed. This involves a technique of alternately stacking organic insulating layers (or insulating films) on the conductor layers of the circuit board.

[0007] Typically, the process of manufacturing a multilayer printed circuit board is carried out in the following order: vacuum laminating a multilayer insulating film onto the inner layer circuitry; pre-curing the insulating film; drilling holes in the insulating film; removing adhesive residue from the insulating film; chemical plating the insulating film; electrolytic plating the insulating film; post-curing the insulating film; and forming the outer layer circuitry.

[0008] Removing adhesive residue from the insulating film involves using an acidic solution to remove the residue (residue derived from the resin components contained in the insulating film) and creating a certain level of roughness by chemically eroding a portion of the insulating film surface. This roughness on the insulating film surface is used to increase adhesion to the copper foil layer in the future.

[0009] Although the initial products used as resin compositions for laminated insulating films consisted of compositions in which epoxy resin and phenolic curing agents were filled with silica particles as inorganic fillers, the demand for low dielectric properties and low CTE has led to a trend towards developing products that use cyanate ester-based curing agents in epoxy resins.

[0010] However, despite the advantages of cured epoxy and cyanate ester resins such as low CTE and low Df, the cured products are susceptible to hydrolysis by residual moisture at high temperatures, which may cause defects due to the deterioration of durability and / or reliability at high temperatures, such as gas generation, bubble formation and mechanical property degradation.

[0011] The advantage of using inorganic fillers with large particle sizes is that the surface roughness formed during the desizing of the insulating film is easily controlled, thus improving adhesion to the copper foil layer. However, a problem arises: it is difficult to process micro-sized through-holes due to the shedding of inorganic filler particles during laser drilling. When using inorganic fillers with small particle sizes of 0.1 μm or larger and less than 0.2 μm to mitigate this problem, the surface roughness formed after the desizing process is too low, resulting in a reduced interlocking effect at the interface with the copper foil layer. Consequently, the aforementioned reliability degradation problem may become even more severe.

[0012] Therefore, there is a need to develop materials that improve durability and / or reliability in high-temperature environments while ensuring advantages such as low CTE and low Df. Summary of the Invention

[0013] Technical issues

[0014] This specification relates to thermosetting resin compositions for solving the above problems, as well as insulating films and printed circuit boards containing the same.

[0015] Technical solution

[0016] The inventors have determined that when epoxy resin is used as the curable resin, cyanate ester resin and phenolic resin are used as curing agents, as well as styrene-maleic anhydride copolymer, and silica with an average particle size of 0.1 μm or larger and less than 0.2 μm is used as the inorganic filler, the advantages of existing cured products of epoxy resin and cyanate ester resin, such as low CTE and low Df, are ensured, while simultaneously ensuring that durability and / or reliability at a certain level or higher are achieved at high temperature environments.

[0017] Therefore, in order to solve the problems in the related art, the exemplary implementation of this specification is as follows.

[0018] An exemplary embodiment of this specification provides a thermosetting resin composition comprising a curable resin, a curing agent, a styrene-maleic anhydride copolymer (SMA), and an inorganic filler, wherein the curable resin comprises an epoxy resin and a phenolic resin, the curing agent comprises a cyanate ester resin, and the inorganic filler comprises silica with an average particle size of 0.1 μm or larger and less than 0.2 μm.

[0019] Another exemplary embodiment of this specification provides an insulating film comprising the above-described thermosetting resin composition and its cured product.

[0020] Another exemplary embodiment of this specification provides a printed circuit board including the above-described insulating film.

[0021] Beneficial effects

[0022] Because the thermosetting resin composition according to this specification has excellent curing physical properties such as a low coefficient of thermal expansion (CTE), a low dielectric constant (Df), and a high glass transition temperature (Tg), warpage can be reduced when the insulating film using the composition is used on a printed circuit board.

[0023] Furthermore, since the thermosetting resin composition according to this specification has excellent durability at high temperatures (about 200°C or higher), reliability can be improved when the insulating film using this composition is used in printed circuit boards in the future.

[0024] Furthermore, since the thermosetting resin composition according to this specification has excellent copper foil adhesion, it can provide the advantage of not causing defects such as bubbles when the insulating film using this composition is used in the future for printed circuit boards. Detailed Implementation

[0025] This instruction manual will be described in more detail below.

[0026] <Thermosetting Resin Composition>

[0027] In the following, a thermosetting resin composition according to an exemplary embodiment of this specification will be described.

[0028] As described above, a thermosetting resin composition according to an exemplary embodiment of this specification is characterized by comprising an epoxy resin as a curable resin, a cyanate ester resin and a phenolic resin as curing agents, and silica as an inorganic filler with an average particle size of 0.1 μm or larger and less than 0.2 μm.

[0029] When the composition is as described above, it can simultaneously possess excellent curing physical properties (low coefficient of thermal expansion, low dielectric constant and high glass transition temperature) and excellent high-temperature durability and reliability.

[0030] According to another exemplary embodiment of this specification, silica may have an average particle size of less than 0.2 μm, 0.19 μm or smaller, or 0.18 μm or smaller, and may have an average particle size of 0.1 μm or larger.

[0031] When the average particle size of silica is within the above range, a certain level of surface roughness can be achieved even after desizing, which is currently required for micro-patterned printed circuit boards. When using silica with an average particle size of at least 0.2 μm, the surface roughness formed due to desizing may be too high, and during laser drilling, the shedding of large silica particles may make it difficult to process vias of the desired size. Furthermore, when using silica with an average particle size of less than 0.1 μm, the surface roughness formed due to desizing may be too low, or the dielectric loss may be high, or the copper foil adhesion may deteriorate. Additionally, when using silica with an average particle size of 0.01 μm or smaller, the film processing itself may become difficult due to the increased solution viscosity.

[0032] In this specification, epoxy resins are not specifically limited to those known in the art, but examples include naphthalene type, phenol type, olefin type, bisphenol A diglycidyl ether (DGEBA) type, bisphenol F diglycidyl ether (DGEBF) type, phenolic varnish type, cresol varnish type, bisphenol type, rubber modified type, etc., and the epoxy resins of the above-exemplified types can be used alone or in mixtures of two or more thereof.

[0033] In this specification, cyanate ester resins are not specifically limited to those known in the art, but examples include phenolic varnish type, dicyclopentadiene type, bisphenol type (bisphenol A type, bisphenol F type, bisphenol S type, etc.), wherein a portion of the cyanate ester resin of the above exemplary types is converted into a triazine prepolymer, etc., and the cyanate ester resins of the above exemplary types can be used alone or in mixtures of both or more thereof.

[0034] In this specification, styrene-maleic anhydride copolymers (SMA) are not specifically limited to those known in the art, but examples include NST-438, SMAEF30, SMAEF40, SMAEF60, SMAEF80, SMA1000, SMA2000, etc., and the SMAs exemplified above can be used alone or in mixtures of both or more thereof.

[0035] According to one exemplary embodiment of this specification, the styrene-maleic anhydride copolymer may contain 10% or more and 40% or less maleic anhydride (based on the whole styrene-maleic anhydride copolymer).

[0036] When the maleic anhydride content in the styrene-maleic anhydride copolymer is less than 10%, the effect of adding it to improve high-temperature durability may be minimal, and when the maleic anhydride content exceeds 40%, the mechanical properties of the final cured product may deteriorate.

[0037] According to an exemplary embodiment of this specification, the content of styrene-maleic anhydride copolymer may be 5 parts by weight or more but less than 40 parts by weight relative to 100 parts by weight of cyanate ester resin.

[0038] When the content of styrene-maleic anhydride copolymer is less than 5 parts by weight relative to 100 parts by weight of cyanate ester resin, the effect on improving high-temperature durability may be minimal, and when the content exceeds 40 parts by weight, the mechanical properties of the final cured product may deteriorate.

[0039] According to an exemplary embodiment of this specification, the curing agent further comprises a phenolic resin, and the weight ratio of the cyanate ester resin to the phenolic resin can be from 95:5 to 40:60. Preferably, the weight ratio of the cyanate ester resin to the phenolic resin can be from 90:10 to 60:40, or from 85:25 to 70:30.

[0040] When cyanate ester resin corresponding to the curing agent is mixed with phenolic resin in the above weight ratio range, the curing speed of the cyanate ester resin is accelerated, and cured products with various mechanical properties can be obtained depending on the type and content of the phenolic resin used. Furthermore, as mentioned above, within the desired range, when the content of phenolic resin is less than the content of cyanate ester resin, fewer hydrophilic OH groups can be formed after curing with epoxy, making it easier to achieve the desired low Df properties.

[0041] According to one exemplary embodiment of this specification, phenolic resins may include compounds comprising a phenolic backbone, a naphthol backbone, or a phenolic varnish backbone.

[0042] According to one exemplary embodiment of this specification, the phenolic resin may be a compound containing a phenolic varnish skeleton.

[0043] When phenolic resins contain the aforementioned skeleton, their heat resistance, water resistance, and other properties can be improved.

[0044] According to an exemplary embodiment of this specification, the weight ratio between epoxy resin and cyanate ester resin can be from 60:40 to 20:80.

[0045] When the weight ratio of epoxy resin to cyanate ester resin is within the above range, no unreacted epoxy resin remains after curing, allowing for further improvement in dielectric and mechanical properties. Furthermore, this weight ratio contributes to improved high-temperature durability. In addition, the excessive self-crosslinking reaction of the cyanate ester resin is controlled, preventing brittle fracture that could easily occur after curing.

[0046] According to an exemplary embodiment of this specification, the thermosetting resin composition further comprises additives, and the additives may be selected from curing accelerators, leveling agents, wetting agents, antistatic agents, thermoplastic polymer resins, and antioxidants.

[0047] In this specification, a curing accelerator is a substance used together with a curing agent to accelerate the curing reaction of a thermosetting resin composition, and is not particularly limited to those known in the art. Examples of such accelerators include imidazole-based compounds, amine-based compounds, organophosphorus compounds, and metal-based compounds. The curing accelerators exemplified above may be used alone or in mixtures of both or more thereof.

[0048] Compounds based on imidazoles may include: 2-methylimidazolium, 2-undecylimidazolium, 2-heptadecylimidazolium, 1,2-dimethylimidazolium, 2-ethyl-4-methylimidazolium, 1,2-dimethylimidazolium, 2-ethyl-4-methylimidazolium, 2-phenylimidazolium, 2-phenyl-4-methylimidazolium, 1-benzyl-2-methylimidazolium, 1-benzyl-2-phenylimidazolium, 1-cyanoethyl-2-methylimidazolium, 1-cyanoethyl-2-undecylimidazolium, 1-cyanoethyl-2-ethyl-4-methylimidazolium, 1-cyanoethyl-2-phenylimidazolium, 1-cyanoethyl-2-undecylimidazolium Trimethicone, 1-Cyanoethyl-2-phenylimidazolium Trimethicone salt, 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 isocyanurate adduct, 2-phenylimidazolyl isocyanurate 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-benzylimidazolium Chloride, 2-methylimidazoline, 2-phenylimidazoline, etc.

[0049] Examples of amine-based compounds include triethylamine, tributylamine, 4-dimethylaminopyridine, benzyldimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol, 1,8-diazabicyclo(5,4,0)-undecene, etc.

[0050] Examples of metal-based compounds include organometallic complexes or organometallic salts of metals such as cobalt, copper, zinc, iron, nickel, manganese, and tin. Specific examples of organometallic complexes include: cobalt(II) acetylacetonate, cobalt(III) acetylacetonate, copper(II) acetylacetonate, zinc(II) acetylacetonate, iron(III) acetylacetonate, nickel(II) acetylacetonate, manganese(II) acetylacetonate, etc. Furthermore, organometallic salts can include zinc octoate, tin octoate, zinc naphthenate, cobalt naphthenate, tin stearate, zinc stearate, etc.

[0051] Furthermore, assuming that the non-volatile contents in the thermosetting resin composition are 100% by mass, the curing accelerator can be used in an amount ranging from 0.01% to 5%.

[0052] In this specification, leveling agents and wetting agents are substances that improve the processability and appearance of coatings by controlling the surface tension, flowability, spreadability, etc. of curable resin compositions, and are not particularly limited to those known in the art.

[0053] In this specification, an antistatic agent is a substance that imparts an antistatic effect, and is not particularly limited to those known in the art. In some cases, an antistatic agent may be used alone or in a mixture of both or more thereof.

[0054] In this specification, thermoplastic polymer resins may be included to improve the mechanical strength, film-forming ability, etc., of the curable resin composition, and are not particularly limited to those known in the art, and examples include phenoxy resins, polyvinyl acetal resins, polyvinyl butyral resins, polyimide resins, polyamide-imide resins, polyether-imide resins, polysulfone resins, polyethersulfone resins, polyphenylene ether resins, polycarbonate resins, polyetheretherketone resins, polyester resins, etc. In some cases, thermoplastic polymer resins may be used alone or in mixtures of both or more thereof. Preferably, the thermoplastic resin includes phenoxy resins. The weight-average molecular weight of the thermoplastic resin can be from 5,000 g / mol to 200,000 g / mol, but is not limited thereto.

[0055] In this specification, antioxidants are substances that improve thermal stability and are not particularly limited to those known in the art. In some cases, antioxidants may be used alone or in mixtures of both or more thereof.

[0056] In one exemplary embodiment of this specification, the thermosetting resin composition may contain a solvent.

[0057] In this specification, when the thermosetting resin composition contains a solvent, the solvent may be used without any particular limitation, as long as it is a known thermosetting resin composition capable of forming the subject of this invention. As a non-limiting example, the solvent may be one or more compounds selected from esters, ethers, ketones, aromatic hydrocarbons, and sulfoxides.

[0058] The ester solvent can be 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, γ-butyrolactone, ε-caprolactone, δ-valerolactone, alkyloxyacetic esters (e.g., methyl oxyacetate, ethyl oxyacetate, butyl oxyacetate (e.g., methyl methoxyacetate, ethyl methoxyacetate, butyl methoxyacetate, methyl ethoxyacetate, ethyl ethoxyacetate, etc.)), alkyl 3-oxypropionic acid esters (e.g., methyl 3-oxypropionic acid, ethyl 3-oxypropionic acid, etc. (e.g., methyl 3-methoxypropionic acid, ethyl 3-methoxypropionic acid, ethyl 3-ethoxypropionic acid)). Methyl propionate, ethyl 3-ethoxypropionate, etc.), alkyl 2-oxypropionates (e.g., methyl 2-oxypropionate, ethyl 2-oxypropionate, propyl 2-oxypropionate, etc. (e.g., methyl 2-methoxypropionate, ethyl 2-methoxypropionate, propyl 2-methoxypropionate, methyl 2-ethoxypropionate, ethyl 2-ethoxypropionate)), methyl 2-oxy-2-methylpropionate and ethyl 2-oxy-2-methylpropionate (e.g., methyl 2-methoxy-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.

[0059] The ether solvent can 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.

[0060] The ketone solvent can be methyl ethyl ketone (MEK), cyclohexanone, cyclopentanone, 2-heptanone, 3-heptanone, N-methyl-2-pyrrolidone, etc.

[0061] Aromatic hydrocarbon solvents can include toluene, xylene, anisole, limonene, etc.

[0062] The sulfoxide solvent can be dimethyl sulfoxide, etc.

[0063] <Insulating film>

[0064] The insulating film according to an exemplary embodiment of this specification will be described below.

[0065] An exemplary embodiment of this specification provides an insulating film comprising the above-described thermosetting resin composition, specifically a laminated insulating film.

[0066] According to this specification, the insulating film can be processed on the circuit in the following sequence: vacuum lamination, pre-curing, drilling, descaling, chemical plating, electrolytic plating, post-curing, and outer layer circuit formation to manufacture printed circuit boards.

[0067] In this specification, the insulating film can be heat-cured (e.g., heat-cured at a temperature of 190°C to 200°C for 90 minutes or longer) to have the following curing properties.

[0068] In one exemplary embodiment of this specification, the coefficient of thermal expansion (CTE) of the insulating film in a cured state at 10 GHz can be 45 ppm / °C or less.

[0069] In another exemplary embodiment of this specification, the coefficient of thermal expansion (for the insulating film) measured in the cured state may be 40 ppm / ℃ or less, 35 ppm / ℃ or less, or 30 ppm / ℃ or less, and may be 15 ppm / ℃ or greater.

[0070] When the coefficient of thermal expansion meets the above range, the difference between the coefficient of thermal expansion and that of the copper foil is small, which has the advantage of small warping after being stacked with the copper foil layer.

[0071] Specifically, after the insulating film is heat-cured at 190°C for 90 minutes, the coefficient of thermal expansion can be measured using a thermometer analyzer (TMA) in the temperature range of 25°C to 120°C.

[0072] In one exemplary embodiment of this specification, the insulating film in a cured state at 10 GHz may have a dielectric constant (Dk) value of 3.5 or less and a dissipation factor (Df) value of 0.015 or less.

[0073] In another exemplary embodiment of this specification, the Dk value of the insulating film measured in the cured state can be 3.4 or less, 3.3 or less, or 3.2 or less, and can be 2.4 or greater.

[0074] In yet another exemplary embodiment of this specification, the Df value of the insulating film may be 0.0145 or less, or 0.014 or less, and may be 0 or greater.

[0075] When the dielectric constant and dissipation factor meet the above ranges, it is beneficial to handle the microwiring and high-speed transmission required for the high integration and high density of semiconductor chips.

[0076] According to an exemplary embodiment of this specification, the difference in adhesion between the insulating film and the copper foil can satisfy the following formula 1.

[0077] A2 / A1 > 0.75 - Equation 1

[0078] In Equation 1,

[0079] A1 is the initial copper foil adhesion force (gf / cm) measured after copper plating on at least one surface of the insulating film, and A2 is the final copper foil adhesion force (gf / cm) measured after a hot air reflow test of the insulating film (performed 10 times at a maximum temperature of 260°C).

[0080] When the above range is met, the high-temperature durability of the insulating film can be assessed as high.

[0081] In one exemplary embodiment of this specification, the average arithmetic mean roughness (Ra) measured on the surface of the desizing insulating film using an optical profilometer (Nanoview 3D surface profilometer NV-2700, Nanosystem) can be 80 nm or greater, 100 nm or greater, or 120 nm or greater, and can be 500 nm or less, 400 nm or less, or 300 nm or less.

[0082] When the surface roughness of the insulating film after deslagging is less than 80 nm, the interlocking effect at the interface with the copper foil is reduced, and additional reliability degradation may occur. When the surface roughness formed after deslagging exceeds 500 nm, the copper foil adhesion is excellent. However, when flash etching is performed after electroplating, the problem is that the plating removal time is prolonged and the wiring shape becomes finer. It is also difficult to apply the insulating film to the micro-linewidth of less than 10 μm required by recent standards.

[0083] Printed Circuit Boards

[0084] In the following, a printed circuit board according to an exemplary embodiment of this specification will be described. Since the printed circuit board includes an insulating film formed from the above-described thermosetting resin composition, the above description regarding the thermosetting resin composition can be applied.

[0085] Invention Embodiments

[0086] In the following description, this specification will be described in detail with reference to embodiments used to specifically describe this specification. However, various modifications may be made to the embodiments described herein, and should not be construed as limiting the scope of this specification to the embodiments described below. Embodiments of this specification are provided to provide a more complete description of this specification to those skilled in the art.

[0087] <Example>

[0088] Example 1: Preparation of thermosetting resin composition 1

[0089] The epoxy resin to be cured consisted of 70 parts by weight of a bisphenol-based epoxy resin (YD-128, KUKDO CHEMICAL CO., LTD.) and 30 parts by weight of a phenolic varnish-type epoxy resin (YDPN-639, KUKDO CHEMICAL CO., LTD.), 112 parts by weight of a dicyclopentadiene bisphenol cyanate ester resin (MEK solution containing 75% non-volatile components, CO3CS, TECHIA), 24 parts by weight of a biphenyl-based phenolic resin (GPH-65, Nippon Kayaku Co., Ltd.), 14 parts by weight of a styrene-maleic anhydride copolymer (MEK solution containing 60% non-volatile components, NST-438, Nanokor Co., Ltd.), and 385 parts by weight of an inorganic filler with an average particle size of 0.18. A silica slurry of μm (containing 60% non-volatile MEK solution, K180SX-CM3, ADMATECHS), 15 parts by weight of phenoxy resin (YP-50, KUKDO CHEMICAL Co., Ltd.) as an additive (thermoplastic polymer resin), and 126 parts by weight of methyl ethyl ketone (MEK) as a solvent were mixed and then stirred at 250 rpm for 3 hours using a mechanical stirrer.

[0090] Subsequently, 1.0 parts by weight of an imidazole-based curing accelerator (2PHZ-PW, Shikoku Chemicals) and 0.05 parts by weight of an inorganic metal-based curing accelerator, cobalt(II) acetylacetonate (TCI), were added, and the resulting mixture was uniformly dispersed by using a high-speed rotary mixer to prepare thermosetting resin composition 1.

[0091] Examples 2 to 5: Preparation of thermosetting resin compositions 2 to 5

[0092] Thermosetting resin compositions 2 to 5 were prepared in the same manner as in Example 1, except that the type and content of each component (based on 100 parts by weight of curable resin (epoxy resin)) were varied during the preparation of the thermosetting resin compositions, as shown in Table 1 below.

[0093] Example 6: Preparation of thermosetting resin composition 6

[0094] Thermosetting resin composition 6 was prepared in the same manner as in Example 1, except that during the preparation of the thermosetting resin composition, the type and content of each component were changed (based on 100 parts by weight of curable resin (epoxy resin)) and the inorganic filler was changed to 385 parts by weight of silica slurry with an average particle size of 0.1 μm (MEK solution containing 60% non-volatile components, SC2050-MB, ADMATECHS), as shown in Table 1 below.

[0095] Comparative Example 1: Preparation of Thermosetting Resin Composition A

[0096] Thermosetting resin composition A was prepared in the same manner as in Example 1, except that styrene-maleic anhydride resin was not added and the content of phenoxy resin (YP-50, KUKDO CHEMICAL CO., LTD.) was changed to 23 parts by weight, as shown in Table 1 below.

[0097] Comparative Example 2: Preparation of Thermosetting Resin Composition B

[0098] Thermosetting resin composition B was prepared in the same manner as in Example 1, except that the inorganic filler was changed to 330 parts by weight of silica slurry with an average particle size of 0.5 μm (MEK solution containing 70% non-volatile components, SC2050-MB, ADMATECHS) and the solvent was changed to 181 parts by weight of methyl ethyl ketone (MEK), as shown in Table 1 below.

[0099] Comparative Example 3: Preparation of Thermosetting Resin Composition C

[0100] Thermosetting resin composition C was prepared in the same manner as in Example 1, except that the inorganic filler was changed to 462 parts by weight of silica slurry (containing 50% non-volatile components of MEK solution, Y50SZ-AM1, ADMATECHS) with an average particle size of 0.05 μm and the solvent was changed to 49 parts by weight of methyl ethyl ketone (MEK), as shown in Table 1 below.

[0101] Comparative Example 4: Preparation of Thermosetting Resin Composition D

[0102] Thermosetting resin composition D was prepared in the same manner as in Example 1, except that no cyanate ester resin was added, the content of phenolic resin (GPH-65, Nippon Kayaku Co., Ltd.) was changed to 108 parts by weight, and the content of solvent was changed to 154 parts by weight of methyl ethyl ketone (MEK), as shown in Table 1 below.

[0103] Comparative Example 5: Preparation of Thermosetting Resin Composition E

[0104] Thermosetting resin composition E was prepared in the same manner as in Example 1, except that phenolic resin was not added, the content of cyanate ester resin (containing 75% non-volatile components of MEK solution, CO3CS, TECHIA) was changed to 144 parts by weight, and the content of solvent was changed to 118 parts by weight of methyl ethyl ketone (MEK), as shown in Table 1 below.

[0105] [Table 1]

[0106]

[0107] Styrene-maleic anhydride copolymer NST-414 (MEK solution containing 60% non-volatile components, maleic anhydride content of 19% by weight, Nanokor Co., Ltd.)

[0108] Styrene-maleic anhydride copolymer NST-438 (MEK solution containing 60% non-volatile components, maleic anhydride content 11% by weight, Nanokor Co., Ltd.)

[0109] <Experimental Example>

[0110] 1. Sample preparation: Preparation of insulating film

[0111] The thermosetting resin compositions prepared in Examples 1 to 6 and Comparative Examples 1 to 5 were used as coating solutions to coat a support film (PET film) with a thickness of 38 μm using an applicator. The support film was then dried at 100°C for 8 minutes to prepare an insulating film sample with a thickness of 25 μm.

[0112] 2. Experimental Example 1: Measurement of permittivity (Dk and Df)

[0113] After each insulating film sample was thermocured at 190°C for 90 minutes, the dielectric constant (Dk) and dielectric loss (Df) were measured at 10 GHz using an SPDR resonator. The measurement results are shown in Table 2 below.

[0114] 3. Experimental Example 2: Measurement of Coefficient of Thermal Expansion (CTE)

[0115] After each insulating film sample was heat-cured at 190°C for 90 minutes, the coefficient of thermal expansion was measured using a TMA (TMA Q400 manufactured by TA Instruments) at a heating rate of 10°C / min in the range of 25°C to 120°C. The measurement results are shown in Table 2 below.

[0116] 4. Experimental Examples 3 and 4: High-Temperature Reliability Assessment

[0117] 1) Removal of adhesive residue

[0118] The insulating film sample was pressed and laminated onto the copper clad laminate (CCL) substrate at 100°C and 0.7 MPa using a vacuum pressure laminator for 30 seconds, then pre-cured in a hot air oven at 100°C for 30 minutes, and then pre-cured at 170°C for 30 minutes.

[0119] Subsequently, the support film (PET film) of the insulator is peeled off to expose the insulation layer, followed by a descaling process. The descaling process is performed using Securiganth MV series treatment solutions manufactured by Atotech in the following sequence: swelling solution treatment (60°C, 5 min) - oxidation solution treatment (80°C, 20 min) - neutralization solution treatment (50°C, 4 min).

[0120] 2) Measurement of surface roughness (Ra, nm) (Experimental Example 3)

[0121] The surface of the debonded insulation layer of each sample was measured 5 times using an optical profilometer (Nanoview 3D Surface Profilometer NV-2700, Nanosystem), and the arithmetic mean roughness (Ra) was determined based on the average value.

[0122] 3) Copper plating treatment

[0123] Copper plating was performed in two stages: electroless chemical copper plating and electrolytic copper plating. Electroless chemical copper plating was performed using Printoganth MV products manufactured by Atotech, resulting in a plating thickness of 1.0 μm. After treatment, the samples were dried in a hot air oven at 150°C for 30 minutes.

[0124] Electrolytic copper plating was performed using Expt Inpro SAP6 chemicals manufactured by Atotech, resulting in a plating thickness of approximately 20 μm. After treatment, the sample was heat-treated in a hot air oven set to 190°C for 1 hour.

[0125] 4) High-temperature reliability assessment

[0126] The high-temperature reliability of copper-plated samples was evaluated using a hot air reflow tester (SEF). The test conditions were a maximum temperature of 260°C, a line speed of 20 cm / min, a line length of 100 cm, and a pass time of 5 minutes. After each sample was passed 10 times, the appearance and copper foil adhesion were determined to assess high-temperature reliability.

[0127] 5) High-temperature reliability assessment (Experimental Example 4)

[0128] The 90-degree peel strength of the copper plating was measured using a texture analyzer (TA-XT Plus) manufactured by Stable Micro Systems. High-temperature reliability was determined as the difference between the initial copper foil adhesion (A1 = adhesion measured after copper plating) and the final copper foil adhesion (A2) described in the high-temperature reliability assessment above.

[0129] Measurements were taken before and after the high-temperature reliability assessment to evaluate high-temperature reliability. Copper foil adhesion was then determined to be poor if it decreased by 25% or more. In other words, it was determined to be poor when the following formula was not met.

[0130] A2 / A1 > 0.75 - Equation 1

[0131] In Equation 1,

[0132] A1 is the initial copper foil adhesion force (gf / cm) measured after copper plating on at least one surface of the insulating film, and

[0133] A2 is the final copper foil adhesion (gf / cm) measured after the insulating film has passed through a hot air reflow tester (SEF) 10 times under the following conditions: a maximum temperature of 260°C, a line speed of 20 cm / min, a line length of 100 cm, and a pass time of 5 minutes.

[0134] Additionally, when the initial copper foil adhesion is less than 400 gf / cm, it is determined to be poor and no high-temperature reliability assessment is performed.

[0135] In addition, following the high-temperature reliability assessment, the appearance was determined, and any appearance defects such as bubble formation or copper foil lifting were considered indicative of poor high-temperature reliability. The results are shown in Table 2 below.

[0136] [Table 2]

[0137]

[0138] According to Table 2 above, in Examples 1 to 6, the materials exhibit a low dielectric constant (Dk) of 3.5 or less, a low dielectric loss (Df) of 0.015 or less, and a low coefficient of thermal expansion (CTE) of 40 ppm / ℃ or less. They also exhibit a surface roughness of 100 nm or greater and 300 nm or less, and excellent copper foil adhesion, thus demonstrating excellent high-temperature reliability. In contrast, in Comparative Example 1, the insulating film using a composition without styrene-maleic anhydride copolymer (SMA) showed low dielectric loss and a low coefficient of thermal expansion, but as a result of the high-temperature reliability assessment, numerous bubbles were generated, and the copper foil adhesion decreased by 25% or more compared to the initial stage, indicating poor high-temperature reliability.

[0139] Furthermore, in Comparative Example 2, the silica particle size is larger than the upper limit of the present invention, resulting in low dielectric loss, low coefficient of thermal expansion, and excellent copper foil adhesion. However, the surface roughness after removing the adhesive residue is 892 nm, which is very high compared to Examples 1 to 6, making Comparative Example 2 difficult to apply to micro-patterning applications.

[0140] In Comparative Example 3, the average particle size of the silica was smaller than the lower limit of the present invention, and therefore, the dielectric loss exceeded 0.015, the coefficient of thermal expansion exceeded 40 ppm / ℃, and the appearance and copper foil adhesion were poor in the high-temperature reliability assessment.

[0141] In Comparative Example 4, no cyanate ester resin was used in the curing agent, and therefore, the coefficient of thermal expansion exceeded 40 ppm / ℃ (which is the highest) and the copper foil adhesion was poor in the high-temperature reliability assessment.

[0142] Comparative Example 5 is a composition in which phenolic resin is not used. It has the lowest dielectric loss (Df) and coefficient of thermal expansion, but has poor copper foil adhesion in the evaluation of high-temperature reliability.

Claims

1. A thermosetting resin composition comprising a curable resin, a curing agent, a styrene-maleic anhydride copolymer (SMA), and an inorganic filler. The curable resin mentioned above includes epoxy resin. The curing agent comprises cyanate ester resin and phenolic resin, and The inorganic filler comprises silica with an average particle size of 0.1 μm or larger and less than 0.2 μm.

2. The thermosetting resin composition of claim 1, wherein the styrene-maleic anhydride copolymer comprises 10% or more and 40% or less maleic anhydride.

3. The thermosetting resin composition according to claim 1, wherein the content of the styrene-maleic anhydride copolymer is 5 parts by weight or more and less than 40 parts by weight relative to 100 parts by weight of the cyanate resin.

4. The thermosetting resin composition according to claim 1, wherein the weight ratio of the cyanate resin to the phenolic resin is from 95:5 to 40:

60.

5. The thermosetting resin composition according to claim 1, wherein the weight ratio between the epoxy resin and the cyanate ester resin is from 60:40 to 20:

80.

6. The thermosetting resin composition according to claim 1, further comprising additives, The additives mentioned therein are selected from curing accelerators, leveling agents, wetting agents, antistatic agents, thermoplastic polymer resins, and antioxidants.

7. An insulating film comprising a thermosetting resin composition according to any one of claims 1 to 6.

8. The insulating film according to claim 7, wherein the coefficient of thermal expansion (CTE) of the insulating film in the cured state at 10 GHz is 45 ppm / ℃ or less.

9. The insulating film according to claim 7, wherein the insulating film in a cured state at 10 GHz has a dielectric constant (Dk) value of 3.5 or less and a dissipation factor (Df) value of 0.015 or less.

10. The insulating film according to claim 7, wherein the difference in copper foil adhesion strength satisfies the following formula: A2 / A1 > 0.75 - Equation 1 In Equation 1, A1 is the initial copper foil adhesion force (gf / cm) measured after copper plating on at least one surface of the insulating film, and A2 is the final copper foil adhesion force (gf / cm) measured after a hot air reflow test of the insulating film (performed 10 times at a maximum temperature of 260°C).

11. A printed circuit board comprising the insulating film according to claim 7.

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