Material capable of delaying cation migration, and prepreg and copper-clad plate prepared from material

Abstract

The invention discloses a material capable of delaying cation migration, a prepreg and a copper-clad core plate. The material is prepared from the following raw materials in parts by weight: 192-213 parts of solid phenolic resin, 137-215 parts of high-bromine epoxy resin, 219-274 parts of multifunctional epoxy resin, 14-17 parts of anti-UV epoxy resin, 20-56 parts of modified epoxy resin, 147-191 parts of inorganic filler, 111-188 parts of organic solvent, 15-20 parts of accelerant and 0.1-1 part of cation exchange resin particles with the particle size of 3-10m. The cation exchange resin particles are introduced into a resin system, passive barrier of a traditional base material is improved into active capture, the cation exchange resin can effectively have an exchange reaction with migrated cations, and the cation exchange resin has the advantages that formation of a leakage current channel is delayed, basic physical properties are not damaged, and the cation exchange resin particles are compatible with an existing manufacturing process; the technical problem of insulation failure caused by the fact that a high-density interconnection printed circuit board is prone to cation migration in a high-temperature and high-humidity bias voltage environment is solved.

Description

Technical Field

[0001] This invention relates to the field of thermosetting resin copper-clad laminates, specifically to a material that can delay cation migration, and the semi-cured film and copper-clad laminate prepared therefrom. Background Technology

[0002] As electronic products become increasingly dense and miniaturized, the number of lines, holes, and interlayer spacing in multilayer circuit boards continues to shrink. Under this trend, a phenomenon known as the Conductive Anodic Filament (CAF) effect, leading to micro-short circuit failures, is becoming increasingly severe. CAF primarily manifests as the gradual oxidation of metallic traces, such as copper, within the resin matrix under an electric field. These copper ions undergo electrochemical migration, migrating along the interface between the resin and reinforcing materials (such as fiberglass cloth and solid fillers) to the cathode and being reduced to metallic copper. This ultimately forms a through-channel conductive path, resulting in decreased insulation resistance and even circuit failure, severely impacting the reliability of electronic products.

[0003] Although existing technologies attempt to improve this phenomenon by enhancing the insulation of the resin or optimizing the surface treatment of the reinforcing material, it is still difficult to completely solve the problem of copper ion migration under extreme environments of high temperature, high humidity and high bias voltage; CAF remains a key problem in multilayer board failure. Summary of the Invention

[0004] In order to overcome the technical defects of existing printed circuit board substrates that are prone to cation migration during long-term use, resulting in decreased insulation performance and short-circuit failure, this invention provides a material that can delay cation migration, a semi-cured film, and a copper-clad laminate.

[0005] To solve the above problems, the present invention is implemented according to the following technical solution:

[0006] The present invention discloses a material that can delay cation migration. This material is a gel solution formed by fully dissolving and mixing the following raw materials, with the following weight proportions of the raw materials:

[0007] The composition includes 192–213 parts of solid phenolic resin, 137–215 parts of high-bromine epoxy resin, 219–274 parts of multifunctional epoxy resin, 14–17 parts of UV-resistant epoxy resin, 20–56 parts of modified epoxy resin, 147–191 parts of inorganic filler, 111–188 parts of organic solvent, 15–20 parts of accelerator, and 0.1–1 parts of cation exchange resin microparticles.

[0008] Preferably, the cation exchange resin microparticles are prepared using the following steps:

[0009] Step 1: Crush the cation exchange resin to obtain fine particles;

[0010] Step 2: Sieve the crushed particles to select cation exchange resin microparticles with a particle size of 3–10 µm;

[0011] Step 3: Mix the above-mentioned microparticles with deionized water in a certain weight ratio, stir with a magnetic rod to remove magnetic impurities, and thus obtain a mixture;

[0012] Step 4: Filter the mixture to remove water and non-magnetic impurities, then dry it to obtain purified cation exchange resin microparticles.

[0013] Preferably, the cation exchange resin is a polystyrene cation exchange resin containing sulfonic acid groups.

[0014] Preferably, the high-bromine epoxy resin has a bromine content of 48-50%; the multifunctional epoxy resin has an epoxy equivalent of 190-300 g / mol; the UV-resistant epoxy resin is a tetrafunctional epoxy resin with an epoxy equivalent of 195-280 g / mol; and the modified epoxy resin is an isocyanate-modified epoxy resin with an epoxy equivalent of 270-350 g / mol.

[0015] Preferably, the inorganic filler is aluminum hydroxide, inorganic silicon, or a mixture thereof; the organic solvent is one or more of acetone, butanone, toluene, and propylene glycol methyl ether; and the accelerator is electronic-grade 2-ethyl-4-methylimidazole.

[0016] Preferably, the present invention also protects a semi-cured film that can delay cation migration, said semi-cured film being made by coating the above-mentioned material that can delay cation migration onto glass fiber cloth.

[0017] Preferably, the semi-cured film is manufactured according to the following method:

[0018] A liquid material that can delay cation migration is coated onto glass fiber cloth and baked at 160-170℃ to obtain a semi-cured film with a gel time of 100-130 seconds.

[0019] Preferably, the present invention also protects a copper-clad laminate that can delay cation migration, the copper-clad laminate being made of the aforementioned prepreg film and copper foil layer.

[0020] Preferably, the copper-clad laminate is manufactured according to the following method:

[0021] The semi-cured film and copper foil layer are heated to a high temperature of 190-220℃ and pressed together with a pressure of 2.0-2.8MPa to obtain the copper-clad core board.

[0022] Preferably, the glass fiber cloth is one or a combination of two of the following electronic grade 7628, 2116, 2113, 3313, 1080, 106, 1027, and 1017:

[0023] The copper foil layer is one or a combination of two of electronic grade HTE, RTF, and HVLP.

[0024] Compared with the prior art, the beneficial effects of the present invention are:

[0025] 1. Possesses an active ion exchange retardation mechanism, significantly extending the CAF failure time.

[0026] This invention introduces cation exchange resin microparticles of a specific particle size (3–10 µm) into the resin system, transforming the traditional substrate's passive barrier (relying solely on resin filling to block copper ion conduction) into a chemically active trapping mechanism. The sulfonic acid groups contained in these microparticles can exchange with migrating copper and sodium ions, significantly delaying the formation of leakage current channels. Under the same resin matrix conditions, only a small amount of ion exchange microparticles is needed to significantly improve the failure time of the CAF, demonstrating excellent resistance to cation migration.

[0027] 2. Exhibits excellent formulation compatibility

[0028] This invention is not limited to a specific resin ratio, demonstrating good formulation adaptability. The cation exchange resin microparticles are compatible with various epoxy resin blends. When combined with multifunctional epoxy resins to increase the glass transition temperature (Tg) of the matrix, the microparticles can still be uniformly dispersed in the resin system, further improving the resistance to cation migration while maintaining the high thermal stability of the substrate (Tg > 180℃). Experiments show that by optimizing the resin ratio, the failure time of the CAF can reach a higher level, fully meeting the requirements of high-reliability applications.

[0029] 3. Precise interface matching enhances the reliability of high-density multilayer boards.

[0030] This invention utilizes cation exchange resin microparticles with a particle size range of 3–10 µm. This particle size range allows for good dispersion in the composite material, forming a uniform ion exchange network within the resin matrix without agglomeration. These microparticles exhibit excellent compatibility with interfacial materials such as glass fiber cloth and copper foil, effectively delaying copper ion migration without affecting interfacial bonding strength, and significantly improving the electrical insulation stability of the substrate under high temperature, high humidity, and bias conditions. It is particularly suitable for high-reliability electronic products such as servers, base stations, and high-end storage systems that require fine lines, narrow aperture spacing, and high-density interconnects.

[0031] 4. Compatible with existing processing techniques and possesses industrial application value.

[0032] The cation exchange resin microparticles described in this invention possess excellent heat resistance and stability, capable of withstanding reflow soldering processes at temperatures above 260°C, without decomposition or failure during PCB manufacturing. Testing has verified that copper-clad laminates with these microparticles maintain excellent levels in key physical properties such as flame retardancy (UL94 V-0), coefficient of thermal expansion (CTE), peel strength, and glass transition temperature, showing no significant difference compared to conventional products without the microparticles. This invention requires no changes to existing PCB processes and equipment, allowing for direct product implementation and application, demonstrating significant industrial implementation value and promising commercialization prospects. Attached Figure Description

[0033] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings, wherein:

[0034] Figure 1 This is a graph showing the CAF test results of the copper-clad laminate prepared using the cation exchange resin material of this invention. Detailed Implementation

[0035] To facilitate understanding of the present invention, the technical solutions and advantages of the invention will be further described in detail below with reference to the accompanying drawings and embodiments. Any mechanisms or methods not elaborated in this invention can be referred to in the prior art. The specific structures and features of the present invention are illustrated below by way of example and should not be construed as limiting the present invention in any way. Furthermore, any of the technical features mentioned below (including implicit or disclosed features), as well as any technical features directly shown or implied in the figures, can be arbitrarily combined or deleted among these technical features to form more other embodiments that may not be directly or indirectly mentioned in this invention. The accompanying drawings show preferred embodiments of the present invention. However, the present invention allows for implementation in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of the present invention.

[0036] Example 1

[0037] In electronic packaging materials, printed circuit boards, and semiconductor devices, metal ions such as copper, silver, and tin are prone to electrochemical migration under electric fields and humid and hot environments. The metal ions dissolve from the anode, migrate along the substrate interface or inside the resin to the cathode and deposit, forming dendrites. This leads to a decrease in insulation resistance between circuits and short-circuit failure, seriously threatening the long-term reliability of electronic products. Although traditional solder resist layers or encapsulating adhesives have a certain physical barrier effect, they are difficult to actively capture or delay the migration of ions. Moreover, conventionally added inorganic fillers or ion capture agents have problems such as poor dispersibility, poor compatibility with resin, introduction of impurity ions, or affecting the curing reaction.

[0038] To address this, the present invention introduces cation exchange resin microparticles of a specific particle size (3–10 µm) into the resin system. This elevates the traditional method of blocking copper ions by simply filling the interface with resin to a chemically active blocking method. The sulfonic acid groups contained in these microparticles can undergo exchange reactions with migrating copper ions, sodium ions, and other cations, fixing them inside the microparticles and effectively blocking ion migration paths, thus significantly delaying the formation of leakage current channels. Under the same resin matrix conditions, only a small amount of ion exchange microparticles is needed to significantly improve the failure time of the CAF, demonstrating excellent resistance to cation migration.

[0039] A material that can delay cation migration comprises a liquid solution formed by fully dissolving and mixing the following raw materials, with the following weight proportions of the raw materials:

[0040] The composition includes 192–213 parts of solid phenolic resin, 137–215 parts of high-bromine epoxy resin, 219–274 parts of multifunctional epoxy resin, 14–17 parts of UV-resistant epoxy resin, 20–56 parts of modified epoxy resin, 147–191 parts of inorganic filler, 111–188 parts of organic solvent, 15–20 parts of accelerator, and 0.1–1 parts of cation exchange resin microparticles.

[0041] The cation exchange resin microparticles in this application are prepared using the following steps:

[0042] Step 1: Crush the cation exchange resin to obtain fine particles;

[0043] Step 2: Sieve the crushed particles to select cation exchange resin microparticles with a particle size of 3–10 µm;

[0044] Step 3: Mix the above-mentioned microparticles with deionized water in a certain weight ratio, stir with a magnetic rod to remove magnetic impurities, and thus obtain a mixture;

[0045] Step 4: Filter the mixture to remove water and non-magnetic impurities, then dry it to obtain purified cation exchange resin microparticles.

[0046] In this application, solid phenolic resin is used as the resin matrix, providing excellent heat resistance, chemical resistance and electrical insulation properties, while also imparting good rheological properties and curing crosslinking density to the adhesive.

[0047] The bromine content of high-bromine epoxy resin is controlled at 48-50%, which gives the material flame-retardant and self-extinguishing properties, and can suppress the spread of combustion without sacrificing electrical performance.

[0048] Multifunctional epoxy resins have an epoxy equivalent of 190–300 g / mol and are used to increase the crosslinking network density and enhance the glass transition temperature.

[0049] The UV-resistant epoxy resin is a tetrafunctional epoxy resin with an epoxy equivalent of 195–280 g / mol, which improves the material's resistance to ultraviolet light and ensures the accuracy of circuit pattern transfer.

[0050] The modified epoxy resin is an isocyanate-modified epoxy resin with an epoxy equivalent of 270–350 g / mol, which improves the flexibility and interfacial adhesion of the cured product, reduces the internal stress of curing shrinkage, and enhances the reliability of interlayer bonding with the substrate.

[0051] Inorganic fillers are selected from aluminum hydroxide, inorganic silicon, or mixtures thereof, which improve thermal conductivity and dimensional stability, and also have the synergistic effect of smoke suppression and flame retardancy.

[0052] The organic solvent is selected from one or more of acetone, butanone, toluene, and propylene glycol methyl ether, and is used to dissolve the resin system and adjust the application viscosity to ensure that the components are uniformly mixed or dispersed.

[0053] The accelerator used is electronic-grade 2-ethyl-4-methylimidazole, ensuring a stable and controllable curing reaction.

[0054] The cation exchange resin microparticles are made of polystyrene cation exchange resin containing sulfonic acid groups, purified through crushing, sieving, magnetic impurity removal, and washing, with a particle size controlled at 3–10 µm. The sulfonic acid groups have exchange adsorption capacity for migratory metal cations such as Cu²⁺ and Ag⁺, which can delay the formation of leakage current channels. Controlling the particle size to 3–10 µm ensures sufficient specific surface area to provide ample exchange sites while preventing the agglomeration of excessively fine particles. Multiple purification processes remove impurities such as iron filings, ensuring that the microparticles themselves do not become a source of impurity ions and avoiding the risk of secondary contamination.

[0055] Example 2

[0056] A semi-cured film that can delay cation migration is made by coating the above-mentioned material that can delay cation migration onto glass fiber cloth;

[0057] The semi-cured film is specifically manufactured according to the following method:

[0058] The material from Example 1 was coated onto fiberglass cloth and baked at 160-170°C to obtain a semi-cured film with a gel time of 100-130 seconds. This gel time window is highly compatible with the multilayer board lamination process, ensuring that the resin has appropriate fluidity during the lamination heating process, which can uniformly fill the gaps in the circuit pattern and simultaneously complete full cross-linking to form a dense insulating layer.

[0059] Fiberglass cloth serves as a reinforcing skeleton, providing dimensional stability, mechanical strength, and heat resistance; while cation exchange resin particles chemically adsorb migrating ions at the vertical or horizontal interface.

[0060] The purified cation exchange resin microparticles maintain their chemical activity and structural integrity during the B-stage baking process. The baking temperature of 160-170℃ is lower than the decomposition temperature of the sulfonic acid groups, allowing the microparticles to remain stable in the B-stage state and during subsequent C-stage curing, continuously performing their ion exchange function. Simultaneously, the microparticles are uniformly distributed within the glass cloth mesh and wire gaps during resin infiltration, ensuring consistent overall anti-migration performance.

[0061] This prepreg film can be directly used in the lamination of multilayer boards, giving the laminate the ability to actively capture migrating ions while maintaining the process adaptability of conventional prepreg films. Compared with conventional prepreg films without added cation exchange resin particles, copper-clad laminates made with the prepreg film of this application exhibit a further slowed rate of decrease in insulation resistance, a delayed dendrite growth initiation time, and a significantly extended service life in 85°C / 85% RH bias tests.

[0062] Example 3

[0063] A copper-clad laminate capable of delaying cation migration is made from a prepreg film prepared in Example 2 and a copper foil layer; specifically, it is prepared by the following method: the prepreg film and the copper foil layer are heated to a high temperature of 190-220°C and pressed together under a pressure of 2.0-2.8 MPa to obtain the copper-clad laminate; wherein the glass fiber cloth is one or a combination of two of electronic grade 7628, 2116, 2113, 3313, 1080, 106, 1027, and 1017; and the copper foil layer is one or a combination of two of electronic grade HTE, RTF, and HVLP.

[0064] The semi-cured film and copper foil layer are heated to 190-220℃ and pressed under pressure of 2.0-2.8MPa to complete the full curing and cross-linking of the resin system from stage B to stage C. The pressing process parameters are fully compatible with the industry standard process window for copper clad laminates, allowing for large-scale production without adjusting existing production line parameters. Under these conditions, the resin flows fully to fill the interface between the fiberglass mesh and the copper foil, forming a non-porous, highly dense insulating layer, while the cation exchange resin particles remain uniformly distributed within the resin.

[0065] After compression curing, the cation exchange resin microparticles are stably anchored in the cross-linked network, and their sulfonic acid groups retain chemical activity, enabling them to continuously perform ion-capturing functions throughout the service life of the copper-clad laminate. The high-temperature compression process does not damage the microparticle structure, and the microparticles do not participate in the curing reaction, ensuring their long-term effectiveness.

[0066] The fiberglass cloth is selected from one or two combinations of electronic-grade 7628, 2116, 2113, 3313, 1080, 106, 1027, and 1017, and can be optimally combined according to different thicknesses, resin contents, and electrical performance requirements. The weaving density and thickness differences of different specifications of fiberglass cloth can adjust the resin flowability and filling capacity of the prepreg, ensuring that the copper-clad laminate has a uniform dielectric layer thickness and stable dielectric properties after lamination. The fiberglass cloth is treated with a coupling agent, exhibiting good interfacial adhesion with resin systems containing cation exchange microparticles.

[0067] The copper foil layer is selected from one or a combination of two of electronic-grade HTE (high-temperature ductile copper foil), RTF (reverse-treated copper foil), and HVLP (ultra-low profile copper foil), which can be matched and selected according to the signal transmission frequency, etching precision, and peel strength requirements. HTE copper foil provides excellent heat resistance and peel strength; RTF copper foil has a surface with controllable roughness, enhancing the anchoring effect with the particulate resin; HVLP copper foil has an extremely low profile, suitable for high-frequency and high-speed signal transmission, reducing skin effect loss. The copper foil and the resin containing cation exchange particles are tightly bonded at the interface, preventing interface pores from becoming weak points for ion migration or moisture intrusion.

[0068] The copper-clad laminate exhibited significantly delayed ion migration behavior in accelerated bias testing at 85°C / 85% RH. Compared to a control copper-clad laminate using conventional prepreg film, the insulation resistance failure rate of the copper-clad laminate in this application was delayed by more than 67 hours. This effect stems from the active chemical capture of migrating ions by cation exchange particles, resulting in a longer service life and higher reliability of the copper-clad laminate under high temperature and high humidity electric field environments.

[0069] This copper-clad laminate can be directly used in the lamination of multilayer boards, and while maintaining the adaptability and mechanical properties of conventional copper-clad laminate processes, it endows the inner core of the circuit board with active resistance to ion migration.

[0070] The present invention will be described in detail below through Examples 1-3 and Comparative Examples 1-5.

[0071] The composition (parts by weight) of the adhesive in each comparative example is shown in Table 1.

[0072] Based on the formulation of each adhesive, semi-cured films and copper-clad laminates were prepared according to the corresponding glass fiber cloth type, coating process, and pressing process parameters. For specific process parameters and material combinations, please refer to the descriptions of each embodiment and comparative example.

[0073] Table 1: Composition of adhesive solutions in each comparative example (parts by weight)

[0074]

[0075] Comparative Example 1

[0076] Preparation of cation exchange resin microparticles

[0077] Cation exchange resin microparticles were prepared according to the following steps:

[0078] Step 1: The polystyrene cation exchange resin containing sulfonic acid groups is crushed to obtain fine particles;

[0079] Step 2: Sieve the crushed particles and select cation exchange resin microparticles with a particle size of 5 µm (range: 3–10 µm);

[0080] Step 3: Mix the above-mentioned microparticles with deionized water at a weight ratio of 1:1, and stir with a magnetic rod for 30 minutes to remove magnetic impurities, thereby obtaining a mixture.

[0081] Step 4: Filter the mixture through a 200-mesh filter to remove water and non-magnetic impurities, and then dry it in an oven at 80°C for 4 hours to obtain purified cation exchange resin microparticles.

[0082] Preparation of materials that can delay cation migration

[0083] Weigh the following raw materials by weight:

[0084] 213 parts of solid phenolic resin (hydroxyl equivalent of 135 g / eq, range: 80~190 g / eq) (range: 192~213 parts).

[0085] 182 parts of high-bromine epoxy resin (bromine content 49%, range: 48-50%) (range: 137-215 parts).

[0086] 220 parts of multifunctional epoxy resin (epoxy equivalent of 200 g / mol, range: 190-300 g / mol) (range: 219-274 parts).

[0087] 14 parts (range: 14 to 17 parts) of UV-resistant epoxy resin (epoxy equivalent of 240 g / mol, range: 195 to 280 g / mol, tetrafunctional).

[0088] 56 parts of modified epoxy resin (epoxy equivalent of 310 g / mol, range: 270-350 g / mol, isocyanate modified) (range: 20-56 parts).

[0089] Inorganic filler: 50 parts aluminum hydroxide, 117 parts inorganic silicon (aluminosilicate) (total of 167 parts inorganic filler, range: 147-191 parts).

[0090] Organic solvents: acetone, butanone, toluene and propylene glycol monomethyl ether are mixed in a ratio of 1:1:1:1, totaling 141 parts (range: 111 to 188 parts).

[0091] Accelerator: 16 parts of electronic grade 2-ethyl-4-methylimidazole (range: 15-20 parts);

[0092] Cation exchange resin microparticles: 0.1 parts (range: 0.1 to 1 part).

[0093] The above raw materials are put into a mixing device and stirred thoroughly at 1000 rpm (range: 800-1200 rpm) for 60 minutes at a temperature of 30℃ (range: 25-35℃) until completely dissolved and dispersed, thus obtaining a uniform gel-like material that can delay cation migration.

[0094] Preparation of semi-cured films that can delay cation migration

[0095] The above-mentioned adhesive solution is evenly coated onto electronic grade glass fiber cloth (model 2116), with the coating thickness controlled at 130μm (range: 120-140μm). It is then baked in an oven at 170℃ (range: 160-170℃) for 4 minutes (range: 3-5 minutes), and the gel time is controlled at 115 seconds (range: 100-130 seconds) to obtain a semi-cured film.

[0096] Preparation of copper-clad laminates that can delay cation migration

[0097] Two prepreg films are stacked together, and an electronic-grade copper foil (model HTE) is applied to each of their upper and lower surfaces. The films are then placed in a hot press and pressed at a maximum temperature of 200℃ (range: 190-220℃) and a pressure of 2.5 MPa (range: 2.0-2.8 MPa) for 90 minutes to obtain a copper-clad laminate that can delay cation migration.

[0098] Comparative Example 2

[0099] Preparation of cation exchange resin microparticles

[0100] The preparation method was exactly the same as that of Comparative Example 1, with a particle size of 6 µm (range: 3–10 µm).

[0101] Preparation of materials that can delay cation migration

[0102] Weigh the following raw materials by weight:

[0103] 203 parts of solid phenolic resin (hydroxyl equivalent of 135 g / eq, range: 80~190 g / eq) (range: 192~213 parts).

[0104] 159 parts of high-bromine epoxy resin (bromine content 49%, range: 48-50%) (range: 137-215 parts).

[0105] 271 parts of multifunctional epoxy resin (epoxy equivalent of 200 g / mol, range: 190-300 g / mol) (range: 219-274 parts).

[0106] 17 parts of UV-resistant epoxy resin (epoxy equivalent of 240 g / mol, range: 195-280 g / mol, tetrafunctional).

[0107] 20 parts of modified epoxy resin (epoxy equivalent of 310 g / mol, range: 270-350 g / mol, isocyanate modified) (range: 20-56 parts).

[0108] Inorganic filler: 38 parts aluminum hydroxide, 132 parts inorganic silicon (aluminosilicate) (total of 170 parts inorganic filler, range: 147-191 parts).

[0109] Organic solvents: acetone, butanone, toluene and propylene glycol methyl ether are mixed in a ratio of 1:1:1:1, totaling 169 parts (range: 111 to 188 parts).

[0110] Accelerator: 20 parts of electronic grade 2-ethyl-4-methylimidazole (range: 15-20 parts);

[0111] Cation exchange resin microparticles: 0.67 parts (range: 0.1 to 1 part).

[0112] The above raw materials are put into a mixing device and stirred thoroughly at 1000 rpm (range: 800-1200 rpm) for 60 minutes at a temperature of 30℃ (range: 25-35℃) until completely dissolved and dispersed, thus obtaining a uniform gel-like material that can delay cation migration.

[0113] Preparation of semi-cured films that can delay cation migration

[0114] The above-mentioned adhesive solution is evenly coated onto electronic grade glass fiber cloth (model 1080), with the coating thickness controlled at 80μm (range: 65-90μm). It is then baked in an oven at 165℃ (range: 160-170℃) for 4 minutes (range: 3-5 minutes), and the gel time is controlled at 115 seconds (range: 100~130 seconds) to obtain a semi-cured film.

[0115] Preparation of copper-clad laminates that can delay cation migration

[0116] Three prepreg films were stacked together, and an electronic-grade copper foil (RTF) was applied to each of their top and bottom surfaces. The films were then placed in a hot press and pressed at a maximum temperature of 210°C (range: 190-220°C) and a pressure of 2.2 MPa (range: 2.0-2.8 MPa) for 90 minutes to obtain a copper-clad laminate that can delay cation migration.

[0117] Comparative Example 3

[0118] Preparation of cation exchange resin microparticles

[0119] The preparation method was exactly the same as that of Comparative Example 1, with a particle size of 8 µm (range: 3–10 µm).

[0120] Preparation of materials that can delay cation migration

[0121] Weigh the following raw materials by weight:

[0122] 192 parts of solid phenolic resin (hydroxyl equivalent of 135 g / eq, range: 80~190 g / eq) (range: 192~213 parts).

[0123] 137 parts of high-bromine epoxy resin (bromine content 49%, range: 48-50%) (range: 137-215 parts).

[0124] 274 parts of multifunctional epoxy resin (epoxy equivalent of 200 g / mol, range: 190-300 g / mol) (range: 219-274 parts).

[0125] 17 parts of UV-resistant epoxy resin (epoxy equivalent of 240 g / mol, range: 195-280 g / mol, tetrafunctional).

[0126] 20 parts of modified epoxy resin (epoxy equivalent of 310 g / mol, range: 270-350 g / mol, isocyanate modified) (range: 20-56 parts).

[0127] Inorganic filler: 40 parts aluminum hydroxide, 141 parts inorganic silicon (aluminosilicate) (total of 181 parts inorganic filler, range: 147-191 parts).

[0128] Organic solvents: acetone, butanone, toluene and propylene glycol monomethyl ether are mixed in a ratio of 1:1:1:2, totaling 188 parts (range: 111 to 188 parts).

[0129] Accelerator: 20 parts of electronic grade 2-ethyl-4-methylimidazole (range: 15-20 parts);

[0130] Cation exchange resin microparticles: 1.0 part (range: 0.1 to 1 part).

[0131] The above raw materials are put into a mixing device and stirred thoroughly at 1000 rpm (range: 800-1200 rpm) for 60 minutes at a temperature of 30℃ (range: 25-35℃) until completely dissolved and dispersed, thus obtaining a uniform gel-like material that can delay cation migration.

[0132] Preparation of semi-cured films that can delay cation migration

[0133] The above-mentioned adhesive solution is evenly coated onto electronic grade glass fiber cloth (model 106), with the coating thickness controlled at 60μm (range: 50-70μm). It is then baked in an oven at 160℃ (range: 160-170℃) for 4 minutes (range: 3-5 minutes), and the gel time is controlled at 115 seconds (range: 100-130 seconds) to obtain a semi-cured film.

[0134] Preparation of copper-clad laminates that can delay cation migration

[0135] Take four of the above-mentioned semi-cured films, cover each of their upper and lower surfaces with a layer of electronic-grade copper foil (model HVLP), place them in a hot press, and press them together at a maximum temperature of 190℃ (range: 190-220℃) and a pressure of 2.0 MPa (range: 2.0-2.8 MPa) for 90 minutes to obtain a copper-clad core board that can delay cation migration.

[0136] Comparative Example 4

[0137] Preparation of cation exchange resin microparticles

[0138] The preparation method was exactly the same as that of Comparative Example 1, with a particle size of 4 µm (range: 3–10 µm).

[0139] Preparation of materials that can delay cation migration

[0140] Weigh the following raw materials by weight:

[0141] 212 parts (range: 192-213 parts) of solid phenolic resin (hydroxyl equivalent of 135 g / eq, range: 80~190 g / eq).

[0142] 215 parts of high-bromine epoxy resin (bromine content 49%, range: 48-50%) (range: 137-215 parts).

[0143] 219 parts of multifunctional epoxy resin (epoxy equivalent of 200 g / mol, range: 190-300 g / mol) (range: 219-274 parts).

[0144] 14 parts (range: 14 to 17 parts) of UV-resistant epoxy resin (epoxy equivalent of 240 g / mol, range: 195 to 280 g / mol, tetrafunctional).

[0145] 56 parts of modified epoxy resin (epoxy equivalent of 310 g / mol, range: 270-350 g / mol, isocyanate modified) (range: 20-56 parts).

[0146] Inorganic filler: 30 parts aluminum hydroxide, 137 parts inorganic silicon (aluminosilicate) (total of 167 parts inorganic filler, range: 147-191 parts).

[0147] Organic solvents: Acetone, butanone, toluene and propylene glycol methyl ether are mixed in a ratio of 1:1:1:2, totaling 111 parts (range: 111 to 188 parts).

[0148] Accelerator: 15 parts of electronic grade 2-ethyl-4-methylimidazole (range: 15-20 parts);

[0149] Cation exchange resin microparticles: 0.5 parts (range: 0.1 to 1 part).

[0150] The above raw materials are put into a mixing device and stirred thoroughly at 1000 rpm (range: 800-1200 rpm) for 60 minutes at a temperature of 30℃ (range: 25-35℃) until completely dissolved and dispersed, thus obtaining a uniform gel-like material that can delay cation migration.

[0151] Preparation of semi-cured films that can delay cation migration

[0152] The above-mentioned adhesive solution is evenly coated onto electronic grade glass fiber cloth (model 2113), with the coating thickness controlled at 100μm (range: 90-110μm). It is then baked in an oven at 168℃ (range: 160-170℃) for 4 minutes (range: 3-5 minutes), and the gel time is controlled at 115 seconds (range: 100~130 seconds) to obtain a semi-cured film.

[0153] Preparation of copper-clad laminates that can delay cation migration

[0154] Two prepreg films are stacked together, and an electronic-grade copper foil (RTF) is applied to each of their upper and lower surfaces. The films are then placed in a hot press and pressed at a maximum temperature of 220°C (range: 190-220°C) and a pressure of 2.8 MPa (range: 2.0-2.8 MPa) for 90 minutes to obtain a copper-clad laminate that can delay cation migration.

[0155] Comparative Example 5

[0156] Preparation of materials that can delay cation migration

[0157] Weigh the following raw materials by weight:

[0158] 212 parts (range: 192-213 parts) of solid phenolic resin (hydroxyl equivalent of 135 g / eq, range: 80~190 g / eq).

[0159] 215 parts of high-bromine epoxy resin (bromine content 49%, range: 48-50%) (range: 137-215 parts).

[0160] 219 parts of multifunctional epoxy resin (epoxy equivalent of 200 g / mol, range: 190-300 g / mol) (range: 219-274 parts).

[0161] 14 parts (range: 14 to 17 parts) of UV-resistant epoxy resin (epoxy equivalent of 240 g / mol, range: 195 to 280 g / mol, tetrafunctional).

[0162] 56 parts of modified epoxy resin (epoxy equivalent of 310 g / mol, range: 270-350 g / mol, isocyanate modified) (range: 20-56 parts).

[0163] Inorganic filler: 30 parts aluminum hydroxide, 137 parts inorganic silicon (aluminosilicate) (total of 167 parts inorganic filler, range: 147-191 parts).

[0164] Organic solvents: Acetone, butanone, toluene and propylene glycol methyl ether are mixed in a ratio of 1:1:1:2, totaling 111 parts (range: 111 to 188 parts).

[0165] Accelerator: 15 parts of electronic grade 2-ethyl-4-methylimidazole (range: 15-20 parts).

[0166] No cation exchange resin particles were added in this comparative example.

[0167] The above raw materials are put into a mixing device and stirred thoroughly at 1000 rpm (range: 800-1200 rpm) for 60 minutes at a temperature of 30℃ (range: 25-35℃) until completely dissolved and dispersed, thus obtaining a uniform adhesive solution.

[0168] Preparation of semi-cured film

[0169] The above-mentioned adhesive solution is evenly coated onto electronic grade glass fiber cloth (model 2113), with the coating thickness controlled at 100μm (range: 90-110μm). It is then baked in an oven at 168℃ (range: 160-170℃) for 4 minutes (range: 3-5 minutes), and the gel time is controlled at 115 seconds (range: 100~130 seconds) to obtain a semi-cured film.

[0170] Preparation of copper clad laminate

[0171] Two prepreg films are stacked together, and an electronic-grade copper foil (RTF) is applied to each of their upper and lower surfaces. The films are then placed in a hot press and pressed at a maximum temperature of 220°C (range: 190-220°C) and a pressure of 2.8 MPa (range: 2.0-2.8 MPa) for 90 minutes to obtain a copper-clad laminate.

[0172] Experimental testing

[0173] Basic physical property testing

[0174] To comprehensively evaluate the impact of this invention on the key performance of copper clad laminate substrates, cured samples prepared by Comparative Examples 1 to 5 were subjected to systematic basic physical property tests according to industry-standard practices. Comparative Example 5 was used as a reference comparative example. The test results are shown in Table 2.

[0175] Table 2: Comparison of Basic Physical Property Test Results

[0176]

[0177] The test results in Table 2 show that:

[0178] Stable and reliable thermal properties

[0179] The glass transition temperatures (DSC Tg and TMA Tg) of all embodiments of the present invention are at the same or better levels than those of other comparative examples. Comparative Examples 2 and 3, due to the use of a higher proportion of multifunctional epoxy resin, have significantly higher Tg values ​​than Comparative Example 5, indicating that the technical solution of the present invention can flexibly adjust the resin ratio to improve heat resistance according to different application requirements. The coefficients of thermal expansion (2.7%–2.8%) of all embodiments in the range of 50–260°C are comparable to those of the comparative examples, proving that the present invention does not negatively affect dimensional stability when the formulation is adjusted according to requirements.

[0180] Safety performance remains intact

[0181] All embodiments achieved the highest UL 94 V0 flame retardant rating, demonstrating that the added cation exchange resin particles did not affect the char formation mechanism and combustion inhibition effect of the main flame retardant system. This invention improves resistance to ion migration while fully maintaining the material's safety performance.

[0182] In summary, when the resin ratio is adjusted in the formulation to meet different needs, the cation exchange resin microparticles introduced in this invention can still stably play a role in delaying the occurrence of failure pathways, significantly improving the anti-CAF performance, and have no negative effect on the basic thermal properties and flame retardant properties of the formulation, demonstrating excellent formulation adaptability and process stability.

[0183] CAF performance test

[0184] To verify the inhibitory effect of the present invention on the failure of conductive anode wire (CAF), the copper-clad laminates prepared by Comparative Examples 1, 2, 3, 4 and 5 were processed into standard CAF test boards (hole spacing 0.45 mm, hole diameter 0.3 mm), and CAF resistance test was performed according to the IPC-TM-650 2.6.25 method.

[0185] The test conditions were: temperature 85℃, humidity 85%, and DC bias voltage 100V. The failure criterion was that the insulation resistance between adjacent holes was less than 1×10⁻⁶. 8 Ω. The test results are shown in Table 3.

[0186] Table 3: CAF test results of cation exchange resin materials:

[0187]

[0188] The test results in Table 3 show that:

[0189] CAF reliability significantly improved

[0190] Comparative Examples 1-4, with the addition of cation exchange resin microparticles, exhibited CAF failure times ranging from 2018 to 2699 hours, all significantly better than Comparative Example 5 (1951 hours) without cation exchange resin microparticles. Comparative Example 3 showed a failure time of 2699 hours. The test results demonstrate that the cation exchange resin microparticles introduced in this invention can effectively exchange with free metal ions under humid, hot, and biased conditions, delaying the formation and growth of CAF pathways at the source, thereby greatly improving the long-term reliability of PCBs under harsh environments.

[0191] Positive correlation between dosage and performance

[0192] Comparative Examples 1, 2, and 3 show that as the amount of cation exchange resin microparticles added increases from 0.1 parts to 1.0 parts, the CAF failure time exhibits a clear increasing trend. Comparative Example 3, with an addition amount of 1.0 parts, achieves the best CAF resistance performance. This trend demonstrates that the 0.1-1.0 part addition range protected by this invention has significant technical effects, and within this range, the technical effect improves with increasing addition amount, providing a clear selection basis for those skilled in the art.

[0193] Synergistic improvement of basic performance and reliability

[0194] As can be seen from the test results in Tables 2 and 3, this invention significantly improves the CAF resistance performance by adding cation exchange resin microparticles, while having no negative impact on the glass transition temperature, coefficient of thermal expansion, and flame retardant rating of the plate.

[0195] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Therefore, any modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A material that can delay cation migration, characterized in that, This material is a liquid adhesive formed by fully dissolving and mixing the following raw materials, with the following weight proportions of the raw materials: The composition includes 192–213 parts of solid phenolic resin, 137–215 parts of high-bromine epoxy resin, 219–274 parts of multifunctional epoxy resin, 14–17 parts of UV-resistant epoxy resin, 20–56 parts of modified epoxy resin, 147–191 parts of inorganic filler, 111–188 parts of organic solvent, 15–20 parts of accelerator, and 0.1–1 parts of cation exchange resin microparticles.

2. The cation migration retardant material according to claim 1, characterized in that, The cation exchange resin microparticles are prepared using the following steps: Step 1: Crush the cation exchange resin to obtain fine particles; Step 2: Sieve the crushed particles to select cation exchange resin microparticles with a particle size of 3–10 µm; Step 3: Mix the above-mentioned microparticles with deionized water in a certain weight ratio, stir with a magnetic rod to remove magnetic impurities, and thus obtain a mixture; Step 4: Filter the mixture to remove water and non-magnetic impurities, then dry it to obtain purified cation exchange resin microparticles.

3. The cation migration retardant material according to claim 2, characterized in that: The cation exchange resin is a polystyrene cation exchange resin containing sulfonic acid groups.

4. The cation migration retardant material according to claim 1, characterized in that: The high-bromine epoxy resin has a bromine content of 48-50%; the multifunctional epoxy resin has an epoxy equivalent of 190-300 g / mol; the UV-resistant epoxy resin is a tetrafunctional epoxy resin with an epoxy equivalent of 195-280 g / mol; and the modified epoxy resin is an isocyanate-modified epoxy resin with an epoxy equivalent of 270-350 g / mol.

5. The cation migration retardant material according to claim 1, characterized in that: The inorganic filler is aluminum hydroxide, inorganic silicon, or a mixture thereof; the organic solvent is one or more of acetone, butanone, toluene, and propylene glycol methyl ether; and the accelerator is electronic-grade 2-ethyl-4-methylimidazole.

6. A semi-cured film capable of delaying cation migration, characterized in that: The semi-cured film is made by coating the cation migration delaying material as described in claims 1-5 onto a glass fiber cloth.

7. The semi-cured film for delaying cation migration according to claim 6, characterized in that, The semi-cured film is specifically manufactured according to the following method: A liquid material that can delay cation migration is coated onto glass fiber cloth and baked at 160-170℃ to obtain a semi-cured film with a gel time of 100-130 seconds.

8. A copper-clad laminate capable of delaying cation migration, characterized in that: The copper-clad laminate is made of the prepreg film and copper foil layer as described in claims 6-7.

9. The copper-clad laminate for delaying cation migration according to claim 8, characterized in that, The copper-clad laminate is manufactured according to the following method: The semi-cured film and copper foil layer are heated to a high temperature of 190-220℃ and pressed together with a pressure of 2.0-2.8MPa to obtain the copper-clad core board.

10. The copper-clad laminate for delaying cation migration according to claim 9, characterized in that: The glass fiber cloth is one or a combination of two of the following electronic grade 7628, 2116, 2113, 3313, 1080, 106, 1027, and 1017: The copper foil layer is one or a combination of two of electronic grade HTE, RTF, and HVLP.

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