Curable composition and insulating film

Abstract

The present disclosure provides a curable composition comprising: (a) a maleimide resin; (b) a cyanate ester; (c) a polyphenylene ether oligomer; (d) a thermoplastic elastomer; (e) an epoxy resin; (f) a curing catalyst; (g) an additive; and (h) an inorganic filler, in particular boron nitride particles. The present disclosure also provides an insulating film comprising the aforementioned curable composition, which is particularly suitable for use in the manufacture of printed circuit boards (PCBs). The insulating film exhibits superior electrical properties, including a low dissipation factor (Df) and a low coefficient of thermal expansion (CTE). Furthermore, the insulating film provides significant advantages in reducing production time in the PCB manufacturing process involving a plasma etching step.

Description

Technical Field

[0001] This disclosure generally relates to a curable composition containing boron nitride, and more particularly to an insulating film and / or printed circuit board comprising the curable composition. Background Technology

[0002] Due to the current trend of electronic products becoming thinner and lighter, printed circuit boards (PCBs) must have higher wiring density. PCBs are typically composed of multiple insulating and conductive layers stacked on top of each other. To achieve high wiring density, vias or blind vias are provided to connect circuits between different conductive layers.

[0003] Conventional via fabrication techniques use lasers as the drilling tool. The friction generated during drilling creates resin contaminants on the channel walls. These contaminants must be removed to achieve optimal bonding. Typically, a wet process is used after laser drilling to remove the contaminants and create suitable through-holes. This wet process includes surface cleaning, contaminant swelling, permanganate decontamination, and neutralization. However, the wastewater discharged at each step carries significant amounts of harmful substances and can potentially degrade the environment and harm human physical and mental health.

[0004] Compared to subtractive or (modified) semi-additive methods in PCB manufacturing, patterning and / or via formation by plasma etching is considered a more environmentally friendly method because it does not involve wet processes.

[0005] However, the etching rate of plasma etching is typically too slow to make PCB manufacturing cost-effective. For example, U.S. Patent Publication No. 20220201853 A1 discloses the use of plasma etching to fabricate multilayer circuit structures with embedded circuit layers, but the materials tested in that patent application exhibited etching rates of less than 1.0 μm / min.

[0006] In view of the above, there is a need to develop new materials for PCB insulation layers, and their ability to be processed by plasma etching technology brings overall benefits to the printed circuit board industry. Summary of the Invention

[0007] To address the aforementioned problems, this disclosure provides a novel resin composition for use as an insulating layer in PCBs. PCBs constructed with this material exhibit high plasma etching rates without sacrificing their electrical and mechanical properties, such as loss factor (Df) and coefficient of thermal expansion (CTE). This novel resin composition is a viable alternative to conventional PCB insulating layers.

[0008] According to one aspect of this disclosure, a curable composition is provided. The curable composition comprises: 100 parts by weight of maleimide resin; 30-150 parts by weight of cyanate ester; 10-100 parts by weight of polyphenylene ether oligomer; 2-75 parts by weight of thermoplastic elastomer; 0.2-25 parts by weight of epoxy resin; 0.02-15 parts by weight of the curing catalyst; 0.02-100 parts by weight of additives; and 120-825 parts by weight of inorganic filler comprising boron nitride particles with a median particle size of 10 μm or smaller.

[0009] According to a second aspect of this disclosure, an insulating film comprising the above-described curable composition is also provided. The insulating film sequentially comprises a support film, a resin layer composed of the above-described curable composition, and a protective film. The resin layer has a thickness of 10 μm to 60 μm.

[0010] According to a third aspect of this disclosure, a printed circuit board is also provided. The PCB includes an insulating layer, which is a cured product of the above-described curable composition or is made of the above-described insulating film. Attached Figure Description

[0011] Figure 1 A cross-sectional view of a test specimen according to an embodiment of the present disclosure is shown. Detailed Implementation

[0012] Before presenting the details of the following embodiments, some terms are defined or clarified. definition

[0013] Unless otherwise stated, all publications, patent applications, patents and other references mentioned herein are expressly incorporated herein in their entirety by reference for all purposes, as if fully expounded.

[0014] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. In case of conflict, this specification (including definitions) shall prevail.

[0015] Unless otherwise stated, all percentages, parts, ratios, etc. are by weight.

[0016] As used herein, the term “produced by” is synonymous with “comprising”. As used herein, the terms “comprises,” “comprising,” “includes,” “including,” “has,” “having,” “contains,” or “containing,” or any other variation thereof, are intended to cover non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises a list of elements is not necessarily limited to those elements, but may include other elements not expressly listed or inherent to such a composition, process, method, article, or apparatus.

[0017] The transitional phrase "composed of..." excludes any unspecified elements, steps, or components. If in a claim, such a phrase limits the claim to exclude materials other than those listed, except typically associated with impurities. When the phrase "composed of..." appears in a clause of the body of a claim, rather than immediately following the preamble, it limits only the elements set forth in that clause; other elements are not excluded from the claim as a whole.

[0018] The transitional phrase “consistently of” is used to define a composition, method, or apparatus that includes, in addition to those discussed literally, materials, steps, features, components, or elements, provided that such additional materials, steps, features, components, or elements do not materially affect the claimed essential and novel features.

[0019] The term "basically composed of" falls in the middle between "contains" and "composes of".

[0020] The term "comprising" is intended to include embodiments covered by the terms "substantially consisting of" and "consisting of". Similarly, the term "substantially consisting of" is intended to include embodiments covered by the term "consisting of".

[0021] When quantities, concentrations, or other values ​​or parameters are given as ranges, preferred ranges, or a series of upper and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pairing of any upper or preferred value with any lower or preferred value, regardless of whether the range is disclosed individually. For example, when the range “1 to 5” is listed, the listed range should be interpreted as including ranges such as “1 to 4”, “1 to 3”, “1-2”, “1-2 and 4-5”, “1-3 and 5”, etc. When numerical ranges are listed herein, unless otherwise stated, the range is intended to include its endpoints, as well as all integers and fractions within that range.

[0022] Furthermore, unless explicitly stated otherwise, "or" refers to an inclusive "or," not an exclusive "or." For example, condition A "or" B is satisfied by any of the following: A is true (or exists) and B is false (or does not exist), A is false (or does not exist) and B is true (or exists), and both A and B are true (or exist).

[0023] This disclosure is described in detail below.

[0024] This disclosure relates to a curable composition comprising: 100 parts by weight of maleimide resin; 30-150 parts by weight of cyanate ester; 10-100 parts by weight of polyphenylene ether oligomer; 2-75 parts by weight of thermoplastic elastomer; 0.2-25 parts by weight of epoxy resin; 0.02-15 parts by weight of the curing catalyst; 0.02-100 parts by weight of additives; and 120-825 parts by weight of inorganic filler comprising boron nitride particles with a median particle size of 10 μm or smaller.

[0025] In one embodiment of this disclosure, the polyphenylene ether oligomer does not contain polyphenylene ether derivatives having groups containing N-substituted maleimide structures.

[0026] In one embodiment of this disclosure, the inorganic filler does not contain silicon dioxide.

[0027] In one embodiment of this disclosure, the curable composition does not contain a modifier selected from the group consisting of: diallyl hexafluorobisphenol A, diallyl bisphenol A, diallyl phthalate, maleimide octasilsesquioxane, fluorinated carbon nanotubes, and montmorillonite.

[0028] In one embodiment of this disclosure, the curable composition does not contain a polymerization initiator.

[0029] In one embodiment of this disclosure, the curable composition comprises 30-100 parts by weight of cyanate ester relative to a total of 100 parts by weight of maleimide resin. In another embodiment of this disclosure, the curable composition comprises 30-90 parts by weight of cyanate ester relative to a total of 100 parts by weight of maleimide resin. In yet another embodiment of this disclosure, the curable composition comprises 30-70 parts by weight of cyanate ester relative to a total of 100 parts by weight of maleimide resin.

[0030] In one embodiment of this disclosure, the curable composition comprises 120-825 parts by weight of an inorganic filler containing boron nitride particles relative to a total of 100 parts by weight of maleimide resin. In another embodiment of this disclosure, the curable composition comprises 120-800 parts by weight of an inorganic filler containing boron nitride particles relative to a total of 100 parts by weight of maleimide resin. In yet another embodiment of this disclosure, the curable composition comprises 150-700 parts by weight of an inorganic filler containing boron nitride particles relative to a total of 100 parts by weight of maleimide resin.

[0031] Non-limiting examples of maleimide resins include maleimides having a biphenyl aryl alkyl backbone; bismaleimides derived from dimer diamines; and bismaleimides comprising 4,4'-diphenylmethane bismaleimide, 3,3'-diphenylmethane bismaleimide, 1,3-phenylene bismaleimide, 1,4-phenylene bismaleimide, m-xylene bismaleimide, p-xylene bismaleimide, and 2,2'-bis[4-(4-maleimide] [N,N'-(4-methyl-1,3-phenylene)bismaleimide, 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethane bismaleimide, 3,3',5,5'-tetramethyldiphenylmethane bismaleimide, N,N'-(4-methyl-1,3-phenylene)bismaleimide, 1,6-bismaleimide hexane, 1,6'-bismaleimide-(2,2,4-trimethyl)hexane, or 4,4'-diphenyl ether bismaleimide, or mixtures thereof.

[0032] Non-limiting examples of cyanate esters include bifunctional or polyfunctional compounds selected from the group consisting of: 2,2-bis(4-cyanooxyphenyl)propane (cyanate ester containing bisphenol A), bis(4-cyanooxyphenyl)methane (cyanate ester containing bisphenol F), dicyclopentadiene-containing cyanate esters, naphthalene-containing cyanate esters, phenolphthalein cyanate esters, adamantane cyanate esters, fluorene cyanate esters, phenolic linear phenolic cyanate esters, and combinations thereof.

[0033] Non-limiting examples of polyphenylene ether oligomers include polyphenylene ether oligomers capped with acrylate groups, epoxy groups, vinyl groups, vinyl benzyl ethers, or hydroxyl groups. However, this disclosure excludes polyphenylene ether derivatives having groups containing N-substituted maleimide structures.

[0034] Non-limiting examples of thermoplastic elastomers include polybutadiene, ethylene-propylene-diene copolymer (EPDM), butadiene-styrene block copolymer, styrene-isoprene-styrene block copolymer (SIS), styrene-ethylene-propylene-styrene block copolymer (SEPS), styrene-ethylene-butene-styrene copolymer (SEBS), or modified products thereof. These polymers / copolymers may be modified with carboxylic acid groups and / or maleic anhydride groups.

[0035] Non-limiting examples of epoxy resins include bisphenol A epoxy resins, bisphenol F epoxy resins, glycidylamine epoxy resins, biphenyl epoxy resins, naphthalene epoxy resins, anthracene epoxy resins, fluorene epoxy resins, biphenyl aralkylphenol epoxy resins, dicyclopentadiene epoxy resins, trihydroxyphenylmethane epoxy resins, naphthol aralkyl epoxy resins, phenol aralkyl epoxy resins, phenol linear phenolic epoxy resins, cresol linear phenolic epoxy resins, bisphenol linear phenolic epoxy resins, naphthol-cresol linear phenolic epoxy resins, naphthyldiol linear phenolic epoxy resins, hydrogenated epoxy resins, halogenated epoxy resins, or combinations thereof.

[0036] Non-limiting examples of curing catalysts include alkylamine catalysts, pyridine catalysts, imidazole catalysts, piperidine catalysts, metal-based curing catalysts, or combinations thereof.

[0037] Non-limiting examples of additives include adhesion promoters, antioxidants, colorants, defoamers, flame retardants, polymerization inhibitors, silane coupling agents, solvents, surface conditioners, thickeners, ultraviolet absorbers, or combinations thereof.

[0038] In one embodiment of this disclosure, the additive is a flame retardant selected from the group consisting of brominated flame retardants, phosphorus flame retardants, nitrogen flame retardants, and combinations thereof.

[0039] In one embodiment of this disclosure, the brominated flame retardant is decabromodiphenyl ether, decabromodiphenyl ethane, brominated styrene, or tetrabromophthalamide.

[0040] In one embodiment of this disclosure, the phosphorus flame retardant is an inorganic phosphorus, a phosphate ester compound, a phosphoric acid compound, a hypophosphoric acid compound, a phosphorus oxide compound, a phosphazene, or a modified phosphazene.

[0041] In one embodiment of this disclosure, the phosphorus flame retardant is 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), 10-(2,5-dihydroxyphenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO-HQ), or tris(2,6-dimethylphenyl)phosphine.

[0042] In one embodiment of this disclosure, the nitrogen flame retardant is a triazine compound, a cyanuric acid compound, an isocyanate compound, or a phenothiazine.

[0043] In one embodiment of this disclosure, the additive is a solvent comprising cyclohexanone, cyclopentanone, isophorone, methyl ethyl ketone, methyl isobutyl ketone, toluene, or a combination thereof.

[0044] A second aspect of this disclosure relates to an insulating film for manufacturing printed circuit boards. The insulating film comprises, in sequence: Support membrane; A resin layer composed of the above curable composition; and Protective film.

[0045] In one embodiment of this disclosure, the resin layer has a thickness of 10 μm to 60 μm. In one embodiment of this disclosure, the support film is a thermoplastic film with a thickness of 10 μm to 50 μm, or a metal foil with a thickness of 1 μm to 25 μm. In one embodiment of this disclosure, the protective film is a thermoplastic film with a thickness of 10 μm to 50 μm.

[0046] In one embodiment of this disclosure, the support film and the protective film are each independently composed of a polymer material selected from the group consisting of: polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate, polyethylene naphthalate, polycarbonate, and polyimide.

[0047] In one embodiment of this disclosure, the support film is a metal foil selected from the group consisting of Au, Ag, Cu, Al, and alloys thereof.

[0048] In one embodiment of this disclosure, the resin layer is cured at 100°C to 250°C for 60 to 240 minutes.

[0049] In one embodiment of this disclosure, the cured resin layer has a loss factor (Df) of 0.006 or less when measured at 10 GHz and 23°C.

[0050] In one embodiment of this disclosure, the cured resin layer has a coefficient of thermal expansion (CTE) of 40 ppm / K or less between 30°C and 120°C.

[0051] In one embodiment of this disclosure, the cured resin layer has a plasma etching rate of 1 μm / min or greater. In another embodiment of this disclosure, the cured resin layer has a plasma etching rate of 1.5 μm / min or greater. Plasma etching is performed for 15 minutes at a chamber pressure of 2 Pa (15 mTorr) by applying a radio frequency (RF) power of 13.56 MHz, an ignition power of 8000 watts, and a DC bias setting of 3000 watts, using a gas mixture of oxygen, tetrafluoromethane (carbon tetrafluoride, CF4), and nitrogen at a ratio of 10:10:1 and a flow rate of 1050 mL / sec.

[0052] A third aspect of this disclosure relates to a printed circuit board comprising an insulating layer, which is a cured product of the above-described curable composition or is made of the above-described insulating film.

[0053] In one embodiment of this disclosure, the circuit is manufactured by a method including a plasma etching step for via and / or trench formation.

[0054] In one embodiment of this disclosure, the method for forming the circuit is a semi-additive process (SAP) or a modified semi-additive process (mSAP). Composition and membrane preparation

[0055] The curable composition disclosed herein comprises the following components: (a) maleimide resin; (b) cyanate ester; (c) polyphenylene ether oligomer; (d) thermoplastic elastomer; (e) epoxy resin; (f) curing catalyst; (g) additives; and (h) inorganic filler. In a non-limiting aspect, the composition aspect of this disclosure can be prepared from the components listed in Table A below. Components (a) to (g) are mixed until completely dissolved to form a base. Component (h): filler is then added to the base and subsequently dispersed uniformly using a rotary mixer. The composition is prepared into two different samples: a resin-coated copper (RCC) film structure and a resin sheet structure for further testing. Table A Example 1

[0056] 25.7 g of MIR3000-70MT (a solution of 70 wt% maleimide resin in a MEK-toluene mixture), 12 g of Primaset BA-200 (cyanate ester resin), 12.3 g of OPE2st 1200 (a solution of 65 wt% PPE resin in toluene), 5 g of Ricon 154 (thermoplastic elastomer), 2 g of NC3000H (epoxy resin), 0.6 g of Lophine (catalyst), 5 g of PX-200 (additive), 10 g of MEK (solvent), and 10 g of toluene (solvent) were mixed and stirred until completely dissolved. Subsequently, 75 g of PCTP05 (filler) was added, and the mixture was uniformly dispersed using a high-speed rotary mixer to prepare a resin varnish.

[0057] The obtained resin varnish was applied to the support film MT18FL-3 μm (two layers of copper foil, with the upper layer being 3 μm thick and the lower layer being 18 μm thick) at a coating speed of approximately 60 mm / s using a suitable quadruple film coater (GMA Machinery, Taiwan) on an automatic coater (Coatmaster 510, purchased from Erichsen GmbH). The coated film was then dried at 100°C for 3 minutes in a circulating oven (DCM704, purchased from Channel Instruments, Taiwan). After drying, the film was covered with 38X (protective film) to form a resin-coated copper (RCC) film structure sample.

[0058] Additionally, the mixed varnish is applied to 38X (protective film) and dried at 100°C for 3 minutes. Then, the dried film is covered with MA411 (protective film) to form a resin sheet structure.

[0059] In both of the above structures, the thickness of the resin composition layer is 30 μm. Example 2

[0060] The resin composition of Example 1, wherein the amount of PCTP05 (filler) is 50 g. Example 3

[0061] The resin composition of Example 1, wherein the amount of PCTP05 (filler) is 34 g. Comparison Example 1

[0062] The resin composition of Example 1, wherein the filler is replaced with SG-SO700 (silica) and the amount is 95 g. Comparison Example 2

[0063] The resin composition of Example 1, wherein the filler is replaced with SG-SO700 and the amount is 50 g. Comparison Example 3

[0064] The resin composition of Example 1, wherein the filler is replaced with SG-SO700 and the amount is 34 g.

[0065] The components of the above examples and comparative examples are listed in Table B. Materials are listed in Table B by their dry weight. The abbreviation "E" stands for "Example," and "CE" stands for "Comparative Example." The examples and comparative examples were prepared in a similar manner. The difference between the examples and the comparative examples lies in the filler. Examples 1-3 used boron nitride as the filler, while comparative examples 1-3 used silica. Table B The median particle size (D50) of boron nitride was measured using a laser scattering particle size distribution analyzer. The filler is based on maleimide resin (100 parts by weight). Measuring the plasma etching rate of RCC films Test sample preparation

[0066] The RCC films from the above examples and comparative examples were further processed as follows to prepare samples for plasma etching tests:

[0067] Lamination: A 15 cm × 20 cm RCC film was laminated onto an EM526 H / H core board (15 cm × 20 cm, 0.6 mm thick) pretreated with CZ-8100 (a pretreatment solution prepared by MEC). The vacuum laminator was heated to 100°C and evacuated for 30 seconds, then pressurized to 7 kgf / cm² at 100°C. 2 Lasts 90 seconds. Curing: Cur the laminated sample in an airflow oven at 130°C for 30 minutes; at 180°C for 30 minutes; and then at 200°C for 90 minutes. Copper removal: After curing, remove the support film MT18FL (the carrier copper of the RCC film). Tenting: A hard mask window (40 μm / 40 μm line / spacing pattern) is formed on the surface of the cured sample (without a carrier). The sample is then cut to a size of 5 cm × 5 cm to be used as a test specimen.

[0068] The structure of the test specimen is in Figure 1 As shown above. The test specimen includes a core layer EM526 (11) and its covering copper (12), a dielectric layer 20 (a curable composition of the present disclosure), and a metal hard mask 30. Subsequent plasma processing will etch the dielectric layer 20 through a window of the hard mask 30. Plasma etching and measurement

[0069] The specimens for both the example and comparative examples were subjected to plasma treatment, and the etching depth was measured using a 3D optical microscope (Olympus Lext OLS5100, 50× objective). The etching depth was calculated as the depth from the surface minus the thickness of the hard mask. The etching rate was calculated by dividing the etching depth by the processing time. The test results for each specimen are listed in Table C. Table C Plasma etching conditions: Ignition 8 kW; bias 3 kW; RF frequency 13.56 MHz; gas flow rates: oxygen 500 cc / min, CF4 500 cc / min, N2 50 cc / min; etching duration 15 minutes.

[0070] As shown in Table C, the plasma etching rates of Examples 1-3 of this disclosure are greater than 1.0 μm / min. The plasma etching rates can further reach greater than 1.5 μm / min. In contrast, Comparative Examples 1-3 have relatively low plasma etching rates and may not be suitable for industrial applications. Measuring Df and CTE of resin sheets Sample preparation

[0071] The resin sheets from the examples and comparative examples were further processed as follows to prepare samples for measuring Df and CTE: Lamination: Multiple resin sheets, each 10 cm × 10 cm in size, are laminated together using a vacuum laminator to form a dielectric layer with a thickness of 60 μm. The vacuum laminator is heated to 100°C and evacuated for 30 seconds, then pressurized to 7 kgf / cm² at 100°C. 2 Lasts 90 seconds. Curing: Cur the laminated sample in an airflow oven at 130°C for 30 minutes; at 180°C for 30 minutes; and then at 200°C for 90 minutes. PET film removal: After curing, remove the protective layer 38X (PET film).

[0072] The loss factor (Df) of the dielectric / insulator was measured at a frequency of 10 GHz using the resonant cavity method. The coefficient of thermal expansion (CTE) was measured using a TA Instruments TMA 650 thermomechanical analyzer. Samples were heated to 280°C, cooled to room temperature, and then reheated at a rate of 5°C / min under a preload of 0.098 N. CTE was calculated as the slope of the dimensional change during the second heating cycle relative to the temperature from 50°C to 100°C. The test results for each sample are listed in Table D. Table D

[0073] The curable compositions disclosed herein are particularly suitable for use in the manufacture of printed circuit boards (PCBs).

[0074] The insulating film containing the curable composition of the present invention exhibits excellent electrical properties, including a low loss factor (Df) and a low coefficient of thermal expansion (CTE). Furthermore, this insulating film offers significant advantages in reducing production time in PCB manufacturing processes involving plasma etching steps. Manufacturing PCBs with curable compositions Step 1: Fabrication of a substrate with existing circuitry

[0075] PCBs with pre-existing circuitry were fabricated using EM526 (core board, 64 μm thick with 22 μm copper thickness, supplied by Elite Electronic Material Co. Ltd.). Step 2: Laminate the RCC sample onto the substrate.

[0076] The RCC sample from Example 1 was laminated onto the substrate using a laminator (Vigor VLPH-150 ton vacuum laminator). After lamination, the lower layer of the support film was removed, and the structure from top to bottom consisted of copper, resin, and the substrate. Step 3: Pattern the metal to form a hard mask

[0077] A photoresist layer is formed by laminating a dry film (Riston® DI61, 15 μm thickness, manufactured by DuPont Electronics, Inc.) onto the copper layer of the substrate from step 2 using a roller laminator at 100°C, 1.4 MPa pressure, and a rolling speed of 1.0 m / min.

[0078] A photoresist pattern was formed using a direct exposure patterning machine (FDi3 from ORC) to create the desired pattern. Uncured portions of the photoresist layer were peeled off and removed by treating with a 2% Na2CO3 solution for 3 minutes, followed by rinsing with DI water and drying.

[0079] Unmasked copper areas were etched away at a rate of 1 m / min along the conventional horizontal line using a sodium persulfate (Na2S2O8) solution (130 g / L) until completion, followed by rinsing with DI water and drying. The photoresist pattern was then stripped and removed by treating with a 10% NaOH solution for 90 seconds, followed by rinsing and drying to form a copper hard mask on the substrate. Step 4: Plasma etching of the dielectric layer

[0080] The exposed areas of the dielectric layer were removed by plasma etching using a reactive ion etching plasma system (manufactured by Linco Tech). The process gas was a mixture of CF4 (500 ml / sec), O2 (500 ml / sec), and N2 (50 ml / sec), ignited at 8 kW and DC biased at 3 kW, for 20 minutes to expose the existing conductor underneath. Step 5: Formation of the seed layer

[0081] The seed layer was formed by sputtering copper using a PVD coating machine (manufactured by UVAT Technology Co., model: UHSD-060302T) with a copper base concentration of 4 N. The resulting copper layer had a thickness of 0.8 μm. Step 6: Adding the photoresist pattern layer

[0082] A dry film (Riston® DI61, 25 μm thickness, manufactured by DuPont Electronics) is laminated onto a copper layer using a roller laminator at 100°C, 1.4 MPa pressure, and a rolling speed of 1.0 m / min to form a photoresist layer.

[0083] Photoresist patterns were formed using a direct exposure patterning machine (FDi3 from ORC) with standard test patterns for PCB manufacturers (including 15 μm / 15 μm line / pitch groups). Uncured portions of the photoresist layer were peeled off and removed by treating with a 2% Na2CO3 solution for 3 minutes, rinsed with DI water, and dried. Step 7: Fill trenches and vias with metal deposition

[0084] Electroplating was applied to fill the trenches and vias with copper. The samples were plated for 40 minutes with a plating solution (SFP2M from DuPont) at 23.13 ASF (amplitude / square feet) for a copper thickness of 22 μm. Step 8: Remove photoresist

[0085] The photoresist pattern was stripped by treating the area with a 10% NaOH solution for 90 seconds. Step 9: Remove the hard mask layer

[0086] Flash etching to remove hard mask layers is performed in the following manner: Immerse the sample in a 5 vol% sulfuric acid aqueous solution for 20 seconds. The sample was transferred to an etching solution (Chemtronic Technologies ST121-M) for 48 seconds. Rinse with DI water to remove any residual solution.

[0087] After the flash etching process, a new circuit layer with vias and wires is completed.

[0088] It will be apparent to those skilled in the art that various modifications and changes can be made to the disclosed embodiments. This specification and examples are intended to be considered merely exemplary, and the true scope of this disclosure is indicated by the following claims and their equivalents.

Claims

1. A curable composition comprising: 100 parts by weight of maleimide resin; 30-150 parts by weight of cyanate ester; 10-100 parts by weight of polyphenylene ether oligomer; 2-75 parts by weight of thermoplastic elastomer; -25 parts by weight of epoxy resin; -15 parts by weight of the curing catalyst; -100 parts by weight of additives; and 120-825 parts by weight of inorganic filler comprising boron nitride particles with a median particle size of 10 μm or smaller.

2. The curable composition of claim 1, wherein, The maleimide resin includes maleimides having a biphenyl aryl alkyl backbone; bismaleimides derived from dimer diamines; and bismaleimides including 4,4'-diphenylmethane bismaleimide, 3,3'-diphenylmethane bismaleimide, 1,3-phenylene bismaleimide, 1,4-phenylene bismaleimide, m-xylene bismaleimide, p-xylene bismaleimide, and 2,2'-bis[4-(4-maleimide-phenyloxy] [N,N'-(4-methyl-1,3-phenylene)bismaleimide, 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethane bismaleimide, 3,3',5,5'-tetramethyldiphenylmethane bismaleimide, N,N'-(4-methyl-1,3-phenylene)bismaleimide, 1,6-bismaleimide hexane, 1,6'-bismaleimide-(2,2,4-trimethyl)hexane, or 4,4'-diphenyl ether bismaleimide, or mixtures thereof.

3. The curable composition of claim 1, wherein, The cyanate ester is a bifunctional or polyfunctional compound selected from the group consisting of: 2,2-bis(4-cyanooxyphenyl)propane (cyanate ester containing bisphenol A), bis(4-cyanooxyphenyl)methane (cyanate ester containing bisphenol F), cyanate ester containing dicyclopentadiene, cyanate ester containing naphthalene, phenolphthalein cyanate, adamantane cyanate, fluorene cyanate, phenol linear phenolic cyanate esters, and combinations thereof.

4. The curable composition of claim 1, wherein, The polyphenylene ether oligomer is a polyphenylene ether oligomer capped with acrylate groups, epoxy groups, vinyl groups, vinyl benzyl ethers, or hydroxyl groups.

5. The curable composition of claim 1, wherein, The thermoplastic elastomer is selected from the group consisting of: polybutadiene, ethylene-propylene-diene copolymer (EPDM), butadiene-styrene block copolymer, styrene-isoprene-styrene block polymer (SIS), styrene-ethylene-propylene-styrene block copolymer (SEPS), styrene-ethylene-butene-styrene copolymer (SEBS), and modified products thereof; wherein the polymer / copolymer is modified with carboxylic acid groups and / or maleic anhydride groups.

6. The curable composition of claim 1, wherein, The epoxy resin is selected from the group consisting of: bisphenol A epoxy resin, bisphenol F epoxy resin, glycidylamine epoxy resin, biphenyl epoxy resin, naphthalene epoxy resin, anthracene epoxy resin, fluorene epoxy resin, biphenyl aralkylphenol epoxy resin, dicyclopentadiene epoxy resin, trihydroxyphenylmethane epoxy resin, naphthol aralkyl epoxy resin, phenol aralkyl epoxy resin, phenol linear phenolic epoxy resin, cresol linear phenolic epoxy resin, bisphenol linear phenolic epoxy resin, naphthol-cresol linear phenolic epoxy resin, naphthyldiol linear phenolic epoxy resin, hydrogenated epoxy resin, halogenated epoxy resin, and combinations thereof.

7. The curable composition of claim 1, wherein, The curing catalyst is selected from the group consisting of: alkylamine catalysts, pyridine catalysts, imidazole catalysts, piperidine catalysts, metal-based curing catalysts, and combinations thereof.

8. The curable composition of claim 1, wherein, The additives are selected from the group consisting of: adhesion promoters, antioxidants, colorants, defoamers, flame retardants, polymerization inhibitors, silane coupling agents, solvents, surface conditioners, thickeners, ultraviolet absorbers, and combinations thereof.

9. The curable composition of claim 1, wherein, The additive is a flame retardant selected from the group consisting of brominated flame retardants, phosphorus flame retardants, nitrogen flame retardants, and combinations thereof.

10. The curable composition of claim 1, wherein, The additive is a solvent comprising cyclohexanone, cyclopentanone, isophorone, methyl ethyl ketone, methyl isobutyl ketone, toluene, or a combination thereof.

11. An insulating film for manufacturing printed circuit boards, the insulating film comprising, in sequence: Support membrane, A resin layer comprising the curable composition as described in claim 1, and Protective film The resin layer has a thickness of 10 μm to 60 μm.

12. The insulating film as claimed in claim 11, wherein, The support film and the protective film are each independently composed of a polymer material selected from the group consisting of: polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate, polyethylene naphthalate, polycarbonate, and polyimide.

13. The insulating film as claimed in claim 11, wherein, The support film is a metal foil selected from the group consisting of: Au, Ag, Cu, Al, and their alloys.

14. The insulating film as claimed in claim 11, wherein, When measured at 10 GHz and 23°C, the cured resin layer has a loss factor (Df) of 0.006 or less, and the curing is carried out at 100°C to 250°C for 60 to 240 minutes.

15. The insulating film as claimed in claim 11, wherein, The cured resin layer has a coefficient of thermal expansion (CTE) of 40 ppm / K or less between 30°C and 120°C, and the curing is carried out at 100°C to 250°C for 60 to 240 minutes.

16. The insulating film as claimed in claim 11, wherein, The cured resin layer has a plasma etching rate of 1 μm / min or greater, and the plasma etching is carried out for 15 minutes at a chamber pressure of 2 Pa (15 mTorr) by applying a radio frequency (RF) power of 13.56 MHz, an ignition power of 8000 watts, a DC bias of 3000 watts, using a gas mixture of oxygen, tetrafluoromethane (carbon tetrafluoride, CF4) in a ratio of 10:10:1 and a flow rate of 1050 mL / sec, and the curing is carried out at 100°C to 250°C for 60 to 240 minutes.

17. A printed circuit board comprising an insulating layer, said insulating layer being a cured product of the curable composition of claim 1.

18. The printed circuit board of claim 17, wherein, The circuit is manufactured by a method including a plasma etching step for forming vias and / or trenches.

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