Composite plating resist film, method for manufacturing the same, and circuit board and method for manufacturing the same

Abstract

The application discloses a composite anti-plating film and a preparation method thereof, a preparation method of an anti-plating material, a circuit board and a preparation method thereof, wherein the composite anti-plating film comprises a structure film layer, a first anti-plating adhesive layer arranged on one side of the structure film layer, and a second anti-plating adhesive layer arranged on the side, away from the structure film layer, of the first anti-plating adhesive layer. The material of the first anti-plating adhesive layer comprises at least one of a high-heat-resistant polymer with an aromatic ring and / or a heterocyclic ring in a main chain and a hot melt adhesive; and the material of the second anti-plating adhesive layer comprises a hot melt adhesive or a composite material of a hot melt adhesive and an inorganic filler with a specific functional group on the surface. The application provides physical support through the structure film layer, and through the design of the double-layer anti-plating adhesive layer with functional differentiation, the composite anti-plating film has excellent chemical resistance and pressure resistance, can be manually removed to realize the peeling characteristics of mild convenience and no residual glue, and has sufficient structural stability to prevent process defects such as hole recession or drill hole peak.

Description

Technical Field

[0001] This invention relates to the field of circuit board manufacturing technology, and in particular to a composite anti-plating film and its preparation method, a method for preparing anti-plating materials, and a circuit board and its preparation method. Background Technology

[0002] In the manufacturing of printed circuit boards (PCBs) and flexible printed circuit boards (FPCs), temporary protective materials are typically required to selectively protect specific copper conductors or functional areas during critical processes such as electroless copper plating, electroplating, etching, or multilayer lamination. Existing methods widely used in the art include the use of photosensitive or non-photosensitive inks or dry films. These protective materials are applied to the surface of non-target processing areas, forming a protective film to resist the effects of subsequent chemical or physical processing. After the relevant processes are completed, this temporary protective film needs to be completely removed to expose the underlying copper conductors or functional areas. However, as electronic products evolve towards higher density, higher frequency, and higher reliability, manufacturing processes are becoming increasingly complex, placing more stringent demands on temporary protective materials.

[0003] On the one hand, traditional ink or dry film protective materials may exhibit insufficient protective capabilities when faced with stronger chemicals (such as strong acid and alkali solutions used in chemical copper plating, browning, or descaling processes) or higher temperature and pressure physical conditions (such as multilayer board lamination). For example, swelling, cracking, or decreased adhesion may occur, leading to protective failure. On the other hand, existing protective material removal processes typically rely on strong alkaline or acidic solutions. This peeling method can cause irreversible damage to increasingly common special substrates or components containing sensitive elements, affecting product yield and long-term reliability. To address this challenge, a gently peelable composite material has been developed. While this material can withstand the erosion of strong acid and alkali solutions, new defects have emerged in practical applications: after undergoing processes (such as PTH, electroplating thickening), its structure softens, resulting in insufficient stability and susceptibility to damage from impacts with hard objects. Furthermore, the protective adhesive may recede from the orifice into the copper surface area (orifice receding defect), affecting processing accuracy. Furthermore, the removal of this material still relies on specific wet stripping equipment, limiting its ease of use and versatility. Additionally, during the drilling process in circuit board manufacturing, burrs are easily generated at the hole edges, requiring effective suppression methods.

[0004] Therefore, how to develop a temporary protective material that can maintain structural integrity under the erosion of strong acid and alkali solutions, prevent burrs and recession during drilling and electroplating, and be completely removed by simple physical means after the protective function is completed without leaving any residue has become a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] The main objective of this invention is to propose a composite anti-plating film, which aims to solve the technical problems of existing temporary protective materials in circuit board manufacturing processes, such as insufficient resistance to chemical corrosion, poor structural stability leading to aperture retraction, and reliance on wet processes for removal, which may damage the substrate.

[0006] To achieve the above objectives, the composite anti-coating film proposed in this invention comprises:

[0007] Structural membranes;

[0008] A first anti-adhesive layer is disposed on one side of the structural film layer;

[0009] The second anti-adhesive layer is disposed on the side of the first anti-adhesive layer that faces away from the structural film layer;

[0010] The material of the first anti-adhesive layer includes a polymer resin, which includes at least one of a high heat-resistant polymer with aromatic rings and / or heterocyclic rings in the main chain and a hot melt adhesive.

[0011] The material of the second anti-adhesive layer includes a hot melt adhesive or a composite material of a hot melt adhesive and an inorganic filler, wherein the surface of the inorganic filler is modified with at least one functional group selected from the group consisting of aniline, alkyl, nitrogen-containing functional groups on the main chain or branches, double-bonded functional groups and epoxy groups.

[0012] In one embodiment, the material of the structural membrane layer is selected from at least one of the group consisting of polyethylene terephthalate, polyethylene naphthalate, polyetherimide, polyphenylene sulfide, ethylene-vinyl acetate copolymer, polyvinyl butyral, polyether ether ketone, nylon, polycarbonate, poly(p-phenylenebenzodioxazole), polyimide, polysulfone, polyphenylene sulfone, liquid crystal polymer, polymethylpentene, polyethylene succinate, polytetrahydrofuran ether glycol, cyclic olefin copolymers, polypropylene-polyethylene-rubber copolymers, polyurethane copolymers, and rubber-polypropylene-polyethylene copolymers.

[0013] In one embodiment, the thickness of the structural film layer is between 9 micrometers and 500 micrometers.

[0014] In one embodiment, on the side where the structural film layer is bonded to the first anti-adhesive layer, the dyne value of the surface of the structural film layer is not less than 30.

[0015] In one embodiment, the softening point of the hot melt adhesive is not less than 40°C.

[0016] In one embodiment, the heat-resistant polymer with an aromatic ring and / or heterocyclic ring in the main chain is selected from at least one of the group consisting of epoxy-phenolic composite resin, polyimide, poly(p-phenylenebenzodioxazole) and polybenzimidazole.

[0017] In one embodiment, the epoxy resin is selected from at least one of glycidylamine epoxy resin, polyfunctional o-cresol glycidyl ether epoxy resin, phenol-biphenyl epoxy resin, bisphenol F solid epoxy resin, isocyanate modified epoxy resin, naphthol epoxy resin, and phenol-formaldehyde epoxy resin.

[0018] In one embodiment, the phenolic resin is selected from at least one of linear phenol-formaldehyde resin and linear BPA-formaldehyde resin.

[0019] In one embodiment, the content of phenolic resin and the content of epoxy resin in the epoxy-phenolic composite resin satisfy the following formula:

[0020] Phenolic resin content = (hydroxyl equivalent of phenolic resin / epoxy equivalent of epoxy resin) × epoxy resin content.

[0021] In one embodiment, the thickness of the first anti-coating layer is between 5 micrometers and 100 micrometers; and / or

[0022] The thickness of the second anti-coating layer is 5 micrometers to 100 micrometers.

[0023] In one embodiment, the hot melt adhesive is selected from at least one of the group consisting of reactive polyurethane hot melt adhesives, polyamide hot melt adhesives, polyolefin hot melt adhesives, ethylene-vinyl acetate copolymer hot melt adhesives, polyethylene hot melt adhesives, and polypropylene hot melt adhesives.

[0024] In one embodiment, the first anti-coating layer further includes the inorganic filler.

[0025] In one embodiment, in the first anti-coating layer, the polymer resin has a weight percentage between 60% and 100%, and the inorganic filler has a weight percentage of no more than 40%.

[0026] In one embodiment, the weight percentage of the inorganic filler in the second anti-plating layer is higher than the weight percentage of the inorganic filler in the first anti-plating layer.

[0027] In one embodiment, in the second anti-coating layer, the weight percentage of the hot melt adhesive is between 5% and 95%, and the weight percentage of the inorganic filler is between 5% and 95%.

[0028] In one embodiment, the inorganic filler is selected from at least one of the group consisting of graphite, carbon black, graphene, fullerene, silicon dioxide, aluminum oxide, aluminum hydroxide, calcium carbonate, magnesium carbonate, magnesium silicate, silicon carbide, titanium carbide, titanium oxide, aluminum hydroxide, magnesium oxide, calcium oxide, boron nitride, and aluminum nitride.

[0029] In one embodiment, the composite anti-plating film further includes a release layer, which is disposed on the side of the second anti-plating adhesive layer opposite to the first anti-plating adhesive layer.

[0030] In one embodiment, the thickness of the release layer is between 9 micrometers and 75 micrometers; and / or

[0031] The release force of the release layer is between 5 g / cm and 500 g / cm.

[0032] In one embodiment, the first anti-coating layer and / or the second anti-coating layer further include a solvent selected from at least one of water, N-methylpyrrolidone, ethanol, acetone, ethyl acetate, n-butyl ether, methyl tert-butyl ether, dimethyl phthalate, butanone, dimethyl sulfoxide, n-butyl ketone, cyclohexanone, toluene, and xylene.

[0033] In one embodiment, the first anti-adhesive layer and / or the second anti-adhesive layer further include additives, said additives including at least one of leveling agents, dispersants, and defoamers.

[0034] In one embodiment, the solvent content in the first anti-coating layer is 0 to 10 times the total weight of the polymer resin; and / or

[0035] In the second anti-adhesive layer, the solvent content is 0 to 10 times the total weight of the hot melt adhesive;

[0036] In the first anti-coating layer, the content of the additive is 0.5% to 5% by weight of the total weight of the polymer resin;

[0037] In the second anti-coating layer, the content of the additive is 0.5% to 5% by weight of the total weight of the hot melt adhesive.

[0038] This invention also proposes a method for preparing anti-plating materials, used to prepare a first anti-plating material and a second anti-plating material, the method comprising the following steps:

[0039] Preparation of resin slurry: The resin components constituting the first anti-plating material or the second anti-plating material are mixed in a first solvent to obtain a resin slurry, wherein the resin component constituting the first anti-plating material includes at least one of a high heat-resistant polymer with aromatic rings and / or heterocycles in the main chain and a hot melt adhesive, and the resin component constituting the second anti-plating material includes a hot melt adhesive.

[0040] Preparation of filler slurry: Surface-modified inorganic fillers are mixed in a second solvent to obtain a filler slurry; and

[0041] Mixing: The filler slurry is added to the resin slurry being stirred to obtain the first anti-plating material or the second anti-plating material in ink form.

[0042] In one embodiment, the method for preparing the resin slurry further includes pre-dissolving at least one additive selected from dispersants, defoamers, and leveling agents into the first solvent; and / or

[0043] In preparing the filler slurry, at least one additive selected from dispersants, defoamers and leveling agents is pre-dissolved in the second solvent.

[0044] In one embodiment, in the step of preparing the first anti-plating material and / or the second anti-plating material, the mixing conditions include at least one of the following:

[0045] The mixing speed for preparing the resin slurry is between 3600 rpm and 7200 rpm, the slurry temperature is not higher than 45°C, and the duration is between 20 minutes and 50 minutes.

[0046] When preparing the filler slurry, the mixing speed is between 3600 rpm and 7200 rpm, the slurry temperature is not higher than 45°C, and the duration is between 20 minutes and 50 minutes.

[0047] When mixing the filler slurry with the resin slurry, the mixing speed is between 3600 rpm and 7200 rpm, the slurry temperature is not higher than 45°C, and the duration is between 60 minutes and 120 minutes.

[0048] In one embodiment, the total weight of the first solvent and / or the second solvent is 0 to 10 times the total weight of the resin components;

[0049] and / or

[0050] The total weight of the additives is 0.5% to 5% of the total weight of the resin components.

[0051] This invention also proposes a method for preparing a composite anti-coating film, comprising the following steps:

[0052] Provide structural membranes;

[0053] A first anti-plating material is applied to one side surface of the structural film layer and a first curing treatment is performed to form the first anti-plating adhesive layer, wherein the first anti-plating material comprises at least one of a high heat-resistant polymer with aromatic rings and / or heterocycles in the main chain and a hot melt adhesive.

[0054] A second anti-plating material is applied to the side of the first anti-plating adhesive layer facing away from the structural film layer, and a second curing treatment is performed to form the second anti-plating adhesive layer. The second anti-plating material includes a hot melt adhesive or a composite material of a hot melt adhesive and an inorganic filler.

[0055] In one embodiment, before coating the first anti-plating material onto the structural film layer, the preparation method further includes:

[0056] The surface of the structural film layer bonded to the first anti-adhesive layer is subjected to surface modification treatment so that the dyne value of the surface of the structural film layer bonded to the first anti-adhesive layer is not less than 30.

[0057] In one embodiment, the first curing process and / or the second curing process includes:

[0058] Drying is carried out for 30 seconds to 90 minutes within a temperature range of 50 degrees Celsius to 150 degrees Celsius.

[0059] In one embodiment, the thickness of the first anti-coating layer is between 1 micrometer and 100 micrometers; and / or

[0060] The thickness of the second anti-coating layer is between 1 micrometer and 100 micrometers.

[0061] In one embodiment, the thickness of the first anti-coating layer is between 3 micrometers and 10 micrometers; and / or

[0062] The thickness of the second anti-coating layer is between 5 micrometers and 20 micrometers.

[0063] In one embodiment, the preparation method further includes:

[0064] A release layer is provided on the side of the second anti-coating layer that faces away from the first anti-coating layer.

[0065] In one embodiment, the thickness of the release layer is between 9 micrometers and 75 micrometers; and / or

[0066] The release force of the release layer is between 5 g / cm and 500 g / cm.

[0067] This invention also proposes a method for manufacturing a circuit board, comprising:

[0068] Provided circuit board: Provided circuit board substrate, wherein the circuit board substrate defines an area to be drilled;

[0069] Applying an anti-plating film: The composite anti-plating film as described in any one of claims 1 to 20 is adhered to the circuit board substrate and covers the area to be drilled, wherein the second anti-plating adhesive layer of the composite anti-plating film is in contact with the circuit board substrate;

[0070] Drilling: Drilling holes in the circuit board substrate to which the composite anti-coating film is attached, so as to form a hole structure in the area to be drilled;

[0071] Copper plating: Copper plating is performed on the circuit board substrate and / or the inner walls of the hole structure; and

[0072] Film removal: Remove the structural film layer of the composite anti-plating film, and detach the first anti-plating layer and the second anti-plating layer from the circuit board substrate.

[0073] In one embodiment, the conditions for attaching the anti-plating film to the surface of the circuit board substrate include:

[0074] The composite anti-coating film is hot-pressed onto the circuit board substrate at a temperature range of 70°C to 150°C and a pressure of 0.1 MPa to 9 MPa for 5 seconds to 30 minutes.

[0075] In one embodiment, the area to be drilled is provided with a conductive metal structure; and / or

[0076] The composite anti-plating film is adhered to one or both sides of the circuit board substrate.

[0077] This invention also proposes a method for manufacturing a circuit board, comprising:

[0078] Provide circuit board: Provide circuit board substrate, wherein a copper plating area is defined on the circuit board substrate;

[0079] Applying an anti-plating film: The composite anti-plating film as described in any one of claims 1 to 20 is adhered to the circuit board substrate and covers the copper area to be plated, wherein the second anti-plating adhesive layer of the composite anti-plating film is in contact with the circuit board substrate;

[0080] Opening a window: removing a local area of ​​the composite resist film corresponding to the copper area to be plated, so as to form at least one opening in the composite resist film and expose the copper area to be plated below the opening;

[0081] Metallization treatment: Metallizing the exposed copper-to-be-plated area within the opening; and

[0082] Film removal: Remove the structural film layer of the composite anti-plating film, and detach the first anti-plating layer and the second anti-plating layer from the circuit board substrate.

[0083] In one embodiment, the area to be plated with copper is provided with a metal conductive structure.

[0084] In one embodiment, the conditions for attaching the composite anti-plating film to the circuit board substrate include:

[0085] The composite anti-coating film is hot-pressed onto the circuit board substrate at a temperature range of 70°C to 150°C and a pressure of 0.1 MPa to 9 MPa for 5 seconds to 30 minutes.

[0086] In one embodiment, the local area corresponding to the copper plating area of ​​the composite anti-plating film is removed by laser ablation.

[0087] In one embodiment, before metallizing the surface of the substrate, the circuit board fabrication method further includes:

[0088] Pickling: The substrate is subjected to pickling treatment to remove adhesive residue generated by the laser ablation.

[0089] In one embodiment, the pickling is performed using a mixed solution containing 30% sulfuric acid and 10% hydrogen peroxide.

[0090] The present invention also proposes a circuit board manufactured using the circuit board preparation method described in any of the preceding claims.

[0091] The composite anti-coating film of this application has the following beneficial effects:

[0092] 1. Excellent chemical and pressure resistance: By using specific high heat-resistant polymers (such as epoxy-phenolic, PI, PBO, PBI, etc.) and optional inorganic fillers to form the first anti-plating layer, combined with a robust structural film layer, the composite film can effectively resist the erosion of strong acid and alkali solutions (such as chemical plating and desizing solutions) in PCB manufacturing processes, and can withstand the high temperature and high pressure conditions in processes such as multilayer board lamination, providing stable and reliable protection for delicate circuits.

[0093] 2. Gentle and convenient peeling characteristics: The second anti-adhesive layer uses a hot-melt adhesive, and in particular, the high content of inorganic fillers is used to precisely control its interfacial bonding force with the substrate. This allows the entire composite film to be completely and cleanly peeled off from the circuit board substrate by physical means (such as manually peeling off the structural film layer) after the protective function is completed. This avoids the damage to the substrate caused by traditional strong acid and strong alkali chemical stripping solutions, and also eliminates the need for specific wet film removal equipment.

[0094] 3. Excellent structural stability to prevent process defects: The presence of the structural film layer provides key physical support for the relatively soft anti-adhesive layer, effectively preventing the softening, shrinkage, and deformation of the peelable material due to insufficient strength during the process (such as when heated or impacted), or causing process defects such as "orifice retraction".

[0095] 4. Suppressing Drill Burrs: When the composite anti-plating film is applied to the substrate for drilling, its structural film layer and adhesive layer can provide effective support for the copper foil exit edge, which helps to suppress the generation of burrs and improve drilling quality.

[0096] 5. Achieving a comprehensive balance of performance: Through an ingenious multi-layer structure design (structural film layer / first anti-adhesive layer / second anti-adhesive layer) and the selection of functionally graded materials (especially by using the inorganic filler content gradient to control the adhesive force), the product successfully balances the often contradictory performance requirements of high protection (chemical resistance, pressure resistance, structural stability) and ease of use (gentle, convenient, and residue-free peeling) in a single product. Attached Figure Description

[0097] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0098] Figure 1 This is a schematic diagram of the structure of an embodiment of the composite anti-coating film of the present invention;

[0099] Figure 2 This is a schematic flowchart of an embodiment of the preparation method of the anti-plating material of the present invention;

[0100] Figure 3 This is a schematic flowchart of an embodiment of the method for preparing the composite anti-coating film of the present invention;

[0101] Figure 4 This is a schematic flowchart of an embodiment of a method for manufacturing a circuit board according to the present invention;

[0102] Figure 5 This is a schematic flowchart of an embodiment of another method for manufacturing a circuit board according to the present invention.

[0103] Explanation of reference numerals: 10, structural film layer; 20, first anti-adhesive layer; 30, second anti-adhesive layer; 40, release layer.

[0104] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0105] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0106] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0107] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the meaning of "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution that simultaneously satisfies A and B. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0108] This invention proposes a composite anti-coating film, which aims to solve the technical problem that existing temporary protection solutions cannot simultaneously possess excellent chemical and pressure resistance, mild and convenient peeling characteristics, and sufficient structural stability to prevent process defects (such as orifice retraction and drill burrs).

[0109] In embodiments of the present invention, such as Figure 1 As shown, the composite anti-plating film includes a structural film layer 10, a first anti-plating adhesive layer 20, and a second anti-plating adhesive layer 30. The first anti-plating adhesive layer 20 is disposed on one side of the structural film layer 10, and the second anti-plating adhesive layer 30 is disposed on the side of the first anti-plating adhesive layer 20 facing away from the structural film layer 10, forming a multi-layered stacked structure with functional gradient.

[0110] Specifically, the structural film layer 10 provides excellent mechanical strength, toughness, and dimensional stability to the relatively soft first resist layer 20 and second resist layer 30. Thus, during stringent processes such as high temperature, high pressure, or chemical immersion in circuit board manufacturing, the structural film layer 10 ensures the entire composite resist film maintains its structural integrity, effectively preventing defects such as shrinkage, deformation, or "orifice retraction" caused by softening of the resist layer, thereby guaranteeing processing accuracy and yield. Furthermore, after all protective processes are completed, the user can easily remove the entire composite resist film from the circuit board surface by peeling off the structural film layer 10.

[0111] In some embodiments, to ensure that the structural membrane 10 can provide stable and reliable physical support, the material of the structural membrane 10 can be a polymer or a mixture of multiple polymers, with the core requirements being excellent mechanical strength, thermal stability, and tolerance to chemicals in the manufacturing process.

[0112] Specifically, the material of the structural film layer 10 may be selected from at least one or a mixture of at least two of the following: polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyetherimide (PEI), polyphenylene sulfide (PPS), polyether ether ketone (PEEK), nylon (PA), polycarbonate (PC), poly(p-phenylenebenzodioxazole) (PBO), polyimide (PI), polysulfone (PSU), polyphenylene sulfone (PPSU), liquid crystal polymer (LCP), polymethylpentene (PMP), polyethylene succinate (PES), polytetrahydrofuran ether diol (PTMG), cyclic olefin copolymer (COC), polypropylene-polyethylene-rubber copolymer (TPE), polyurethane copolymer (TPU), rubber-polypropylene-polyethylene copolymer (TPR), ethylene-vinyl acetate copolymer (EVA), and polyvinyl butyral (PVB).

[0113] It is understandable that the above-mentioned materials were chosen as the structural film layer 10. On the one hand, high-performance organic polymers such as polyimide (PI) and polyetheretherketone (PEEK) contain a large number of aromatic rings and / or heterocyclic structures in their molecular backbone, which endows them with extremely high glass transition temperatures (Tg) and excellent dimensional stability. When the composite anti-plating film of the present invention is applied to high-temperature PTH or lamination processes, the structural film layer 10 composed of these materials will not soften, stretch, or deform, thereby providing a robust and stable platform for the anti-plating layer that may soften, effectively preventing protective defects caused by thermal stress. On the other hand, engineering plastics such as polyethylene terephthalate (PET) and polycarbonate (PC), as well as materials such as cyclic olefin copolymers (COC), have excellent mechanical toughness and tensile strength. During the drilling or transportation of circuit boards, the structural film layer 10 composed of these materials can resist physical impacts and friction, protecting the anti-plating layer from scratches or damage, and ensuring the integrity of the protective function. At the same time, its good toughness also makes it easy to perform a complete, unbroken tearing operation after all processes are completed.

[0114] In some embodiments, the thickness of the structural membrane layer 10 is selected to achieve an optimal balance between mechanical support performance and processing applicability. Specifically, the thickness of the structural membrane layer 10 can be any value between 9 micrometers and 500 micrometers. For example, the thickness of the structural membrane layer 10 can be 9 micrometers, 25 micrometers, 50 micrometers, 75 micrometers, 125 micrometers, 200 micrometers, 300 micrometers, 400 micrometers, 500 micrometers, etc., and the present invention is not limited thereto.

[0115] Understandably, on the one hand, when the thickness of the structural film layer 10 is not less than 9 micrometers, it ensures sufficient mechanical strength and rigidity, thus providing stable and reliable physical support for the resist layer throughout the entire circuit board manufacturing process, effectively preventing unnecessary deformation or shrinkage. Simultaneously, this thickness also ensures that the composite resist film has sufficient toughness during final removal, making it less prone to breakage and facilitating complete and rapid peeling by the operator. On the other hand, when the thickness of the structural film layer 10 is not greater than 500 micrometers, it ensures that the entire composite resist film maintains good flexibility and conformability, allowing it to easily conform to the microscopic undulations of the circuit board surface, avoiding gaps caused by excessively hard materials, thereby ensuring the tightness of the protection. Furthermore, an appropriate thickness also benefits subsequent processing steps such as drilling, avoiding adverse effects caused by excessively thick film layers.

[0116] Preferably, the thickness of the structural film layer 10 is between 10 micrometers and 100 micrometers. That is, the thickness of the structural film layer 10 can be any value between 10 micrometers and 100 micrometers.

[0117] In some embodiments, in order to ensure that the first anti-adhesive layer 20 can form a strong and reliable interlayer bond with the structural film layer 10, the surface dyne value of the structural film layer 10 is not less than 30 on the bonding side between the structural film layer 10 and the first anti-adhesive layer 20.

[0118] Specifically, the dyne value is a unit that measures the surface tension or surface energy of a material. It is commonly used to assess the wettability and adhesion of a material's surface, especially in processes such as coating, bonding, or printing. The full name of the dyne value is "dyne per centimeter" (dyne / cm), and 1 dyne / cm equals 1 mN / m (millineutons per meter). It is the international unit of surface tension. The higher the surface tension, the larger the dyne value, and the easier it is for liquids (such as coatings and adhesives) to spread on the surface, resulting in better adhesion.

[0119] It is understandable that this limitation on the surface dyne value of the structural film layer 10 is technically aimed at increasing its surface energy, thereby improving the wettability and adhesion of the first anti-adhesive layer 20 on its surface. The original surface of polymer materials is typically a low-surface-energy, non-polar surface. If the liquid first anti-adhesive layer 20 is directly applied to the untreated surface of the structural film layer 10, it may lead to coating shrinkage, poor adhesion, and eventual delamination failure during product use. By employing surface modification methods such as corona treatment, plasma treatment, or flame treatment, the surface energy of the structural film layer 10 can be effectively increased, ensuring its dyne value is not less than 30. When the dyne value reaches this level, the surface polarity of the structural film layer 10 is significantly enhanced, enabling it to form good wetting with the liquid first anti-adhesive layer 20, thus resulting in strong physical adsorption and chemical bonding after curing. This ensures that the first anti-coating layer 20 can be uniformly and firmly attached to the structural film layer 10, so that the composite anti-coating film can still maintain its structural integrity and will not peel off between layers in harsh environments such as subsequent bending, high temperature or chemical immersion.

[0120] In a preferred embodiment, the surface dyne value of the structural membrane layer 10 is set to be not less than 54 in order to obtain better interlayer bonding strength.

[0121] The first anti-coating layer 20 is directly bonded to the structural film layer 10. On the one hand, it needs to resist the erosion of chemicals such as strong acids and strong alkalis. On the other hand, its own chemical composition allows the entire composite anti-coating film to be gently peeled off without the need to use strong chemical stripping liquids that damage the substrate.

[0122] To achieve the above functions, the first anti-adhesive layer 20 is made of a specially formulated polymer resin. Specifically, the polymer resin includes at least one of a high heat-resistant polymer with aromatic rings and / or heterocyclic rings in its main chain and a hot melt adhesive.

[0123] Specifically, the main chain refers to the longest and most essential skeletal chain that makes up the polymer. Aromatic rings typically refer to highly stable planar ring structures like benzene rings. Heterocyclic rings, on the other hand, are ring structures that contain not only carbon atoms but also other elements such as nitrogen (N) and oxygen (O). This highly heat-resistant polymer can be composed entirely of aromatic rings or a combination of aromatic and heterocyclic rings.

[0124] Therefore, the presence of aromatic rings and / or heterocycles in the main chain means that, unlike simple, flexible chains like polyethylene composed of carbon-carbon single bonds, the molecular backbone of these high-heat-resistant polymers is composed of a large number of highly stable and rigid ring structures directly linked together. This rigid cyclic main chain has high chemical bond energy and a dense structure, thus exhibiting extremely high chemical inertness and thermal stability. Using this type of polymer as the main component of the first anti-adhesive layer 20 can endow the layer with excellent heat resistance (high Tg point) and chemical resistance (resistance to strong acids and alkalis), ensuring that it maintains structural integrity and protective capabilities during high-temperature pressing or chemical immersion.

[0125] Specifically, the high heat-resistant polymer can be selected from at least one of the group consisting of epoxy-phenolic composite resin, polyimide (PI), poly(p-phenylenebenzodioxazole) (PBO), and polybenzimidazole (PBI). Among these, epoxy-phenolic composite resin refers to a composite resin of epoxy resin and phenolic resin.

[0126] When selecting epoxy-phenolic composite resins, the epoxy resin can be selected from at least one of the following: glycidylamine epoxy resin, polyfunctional o-cresol glycidyl ether epoxy resin, phenol-biphenyl epoxy resin, bisphenol F solid epoxy resin, isocyanate modified epoxy resin, naphthol epoxy resin, and phenolic epoxy resin. These epoxy resins have different molecular structures and functionalities, and can be selected or combined according to the specific requirements for the final properties (such as Tg point, toughness, and bond strength).

[0127] Specifically, the epoxy resin material used in this invention has an epoxy molecular weight of 2500 g / mol to 6000 g / mol.

[0128] The structural formula of glycidylamine epoxy resin is: Its epoxy equivalent is between 93 and 150 g / eq, its hydrolytic chlorine content is less than 200 ppm, and its viscosity at 25°C is between 0.5 and 5 Poise.

[0129] The structural formula of the functional o-cresol-formaldehyde glycidyl ether type epoxy resin is: Its epoxy equivalent ranges from 195 to 230 g / eq, its hydrolytic chlorine at 120℃ ranges from 470 to 1000 g / eq, its ICI viscosity at 150℃ ranges from 0.9 to 60 Poise, and its softening point ranges from 45 to 96℃.

[0130] The structural formula of phenol-biphenyl epoxy resin is: Its epoxy equivalent ranges from 261 to 280 g / eq, hydrolytic chlorine content is less than 100 ppm, viscosity at 25°C is between 0.1 and 4.5 Poise, and softening point is 45 to 75°C. Adding it to PVB and its hydroxyl copolymerization can effectively improve the glass strength, Tg, and impact resistance of copper.

[0131] The structural formula of bisphenol F solid epoxy resin is: Its epoxy equivalent ranges from 450 to 1000 g / eq, hydrolytic chlorine content is less than 300 ppm, viscosity at 25°C is <1000 Poise, and softening point is 50 to 88°C. Solid bisphenol F type epoxy resin is characterized by low viscosity and flexibility. The properties of its cured product are almost identical to those of bisphenol A type epoxy resin. Adding it to PVB for copolymerization with its hydroxyl groups can effectively improve its corrosion resistance.

[0132] The structural formula of isocyanate-modified epoxy resin is:

[0133] Its epoxy equivalent ranges from 280 to 380 g / eq, hydrolytic chlorine content is less than 300 ppm, viscosity at 25°C is between 0.5 and 3 Poise, and softening point is 50 to 88°C. Solid isocyanate-modified epoxy resin is characterized by low viscosity and flexibility. The properties of its cured product are almost identical to those of bisphenol A type epoxy resin. Adding it to PVB and copolymerizing it with its hydroxyl groups can effectively improve bond strength and peel strength.

[0134] The structural formula of naphthol-type epoxy resin is: Its epoxy equivalent ranges from 280 to 380 g / eq, hydrolytic chlorine content is less than 300 ppm, viscosity at 25°C is between 0.5 and 3 Poise, and softening point is 50 to 88°C. Among them, naphthol-type epoxy resins are superior to traditional bisphenol A type in terms of curing properties, heat resistance, and mechanical properties. Furthermore, due to its lower internal stress, it has a higher Tg and better adhesion. When added to structural resins and copolymerized with its hydroxyl groups, it can effectively improve the Tg point, bond strength, and peel strength.

[0135] The structural formula of phenolic epoxy resin is: Its epoxy equivalent ranges from 165 to 200 g / eq, hydrolytic chlorine content is less than 250 ppm, viscosity at 25°C is between 1.1 and 12.5 Poise, and softening point is 25 to 86°C. Phenolic epoxy resins have two or more epoxy groups in their molecular structure. Therefore, when added to structural resins and copolymerized with their hydroxyl groups, the resulting product has a high crosslinking density and excellent adhesive strength, heat resistance, and chemical resistance. Furthermore, the presence of two or more epoxy groups in the molecular structure of phenolic epoxy resins leads to a high crosslinking density in the cured product, resulting in excellent adhesive strength, heat resistance, and chemical resistance. General-purpose PVB is compatible with low-molecular-weight epoxy resins, while high-molecular-weight epoxy resins require PVB with a high acetal degree for compatibility.

[0136] Furthermore, the phenolic resin used in conjunction with the epoxy resin can be selected from at least one of linear phenol-formaldehyde resin and linear BPA-formaldehyde resin. These phenolic resins mainly serve as curing agents for the epoxy resin, forming a cross-linked network through the reaction of phenolic hydroxyl groups with epoxy groups.

[0137] Specifically, the structural formula of linear phenol-formaldehyde resin is: Its free phenol content is <0.6%, and its softening point is 96~123. o C, with a hydroxyl equivalent between 105 and 119 g / eq and an electrical conductivity less than 8 μS / cm.

[0138] The structural formula of linear BPA formaldehyde resin is: Its free phenol content is 1-45%, and its softening point is 90-140°C. o C, hydroxyl equivalent between 112 and 130 g / eq, and conductivity less than 20 μS / cm.

[0139] Choosing these phenolic resins, especially those with low free phenol content and low electrical conductivity, helps ensure the stability of the curing reaction and the electrical insulation performance of the final protective layer.

[0140] To obtain optimal curing properties (such as the highest crosslinking density, heat resistance, and mechanical strength), the content of phenolic resin and epoxy resin should preferably satisfy the principles of stoichiometry, i.e., the following formula:

[0141] Phenolic resin content = (hydroxyl equivalent of phenolic resin / epoxy equivalent of epoxy resin) × epoxy resin content.

[0142] Here, "epoxy equivalent weight (EEW)" refers to the number of grams of epoxy resin containing 1 mole of epoxy groups, while "hydroxyl equivalent weight (EEW)" refers to the number of grams of phenolic resin containing 1 mole of phenolic hydroxyl groups. These two values ​​are key parameters for measuring the reactivity of the resin. Therefore, the essence of the above formula is a mathematical conversion of the chemical equilibrium relationship of "moles of phenolic hydroxyl groups ≈ moles of epoxy groups". By using this formula, the amount of phenolic resin containing an equal number of reaction sites can be accurately calculated based on the amount of epoxy resin used and its epoxy equivalent weight.

[0143] The fundamental reason for using the above formula to determine the amount of the two resins is that it follows the stoichiometric principle in chemical reactions, aiming to achieve an ideal balance in the number of the two core functional groups participating in the reaction—the phenolic hydroxyl groups (-OH) on the phenolic resin molecular chain and the epoxy groups on the epoxy resin molecular chain—so as to obtain the curing product with the best performance.

[0144] Specifically, the curing process of the bonding-enhancing resin mainly involves a ring-opening addition reaction between phenolic hydroxyl groups and epoxy groups, forming a highly cross-linked three-dimensional network structure. To ensure this reaction proceeds most completely and efficiently, theoretically, one phenolic hydroxyl functional group should react with exactly one epoxy functional group. Therefore, the ideal feed ratio should make the total molar ratio of phenolic hydroxyl groups to epoxy groups in the formulation as close to 1:1 as possible. Epoxy equivalent (EEW) refers to the number of grams of epoxy resin containing 1 mole of epoxy groups, and hydroxyl equivalent (HEW) refers to the number of grams of phenolic resin containing 1 mole of phenolic hydroxyl groups. By using this formula, the amount of phenolic resin to match it can be accurately calculated based on the amount of epoxy resin selected and its epoxy equivalent.

[0145] It is understandable that using this stoichiometric method to determine the proportions ensures the full progress of the crosslinking reaction and avoids the formation of a large number of unreacted functional groups in the cured network due to an excess of any one component. This results in the highest crosslinking density of the final cured bonding-strengthening resin, thereby achieving superior heat resistance, chemical resistance, and the strongest mechanical strength and adhesion to the substrate.

[0146] The polymer resin of the first anti-adhesive layer 20 may also include a hot melt adhesive. Specifically, the hot melt adhesive is a heat-activated adhesive, where heat activation refers to melting and flowing the material through heating, thereby achieving effective wetting and bonding to the substrate. Specifically, after being heated to a certain temperature, the hot melt adhesive changes from a solid to a liquid state, exhibiting low viscosity and flow characteristics, enabling it to spread evenly on the substrate surface and form a tight contact interface. During the cooling process, the hot melt adhesive forms a strong bond through physical solidification or partial chemical cross-linking.

[0147] In some embodiments, the hot melt adhesive may be selected from at least one group consisting of reactive polyurethane (PUR) hot melt adhesives, polyamide (PA) hot melt adhesives, polyolefin (PO) hot melt adhesives, ethylene-vinyl acetate copolymer (EVA) hot melt adhesives, polyethylene (PE) hot melt adhesives, and polypropylene (PP) hot melt adhesives. The introduction of these hot melt adhesives can modulate the processing properties of the material or be compounded with other components to obtain specific properties.

[0148] Among these, the structural formula of reactive polyurethane (PUR) hot melt adhesive is:

[0149] .

[0150] The structural formula of polyamide (PA) hot melt adhesive is: .

[0151] The structural formula of polyolefin (PO) hot melt adhesive is: and .

[0152] The structural formula of ethylene-vinyl acetate copolymer (EVA) hot melt adhesive is: .

[0153] The structural formula of polyethylene (PE) hot melt adhesive is: .

[0154] The structural formula of polypropylene (PP) hot melt adhesive is: .

[0155] It is understood that by employing a polymer resin containing at least one of a high heat-resistant polymer with aromatic rings and / or heterocyclic rings in its main chain and a hot-melt adhesive, the first anti-plating layer 20 is not limited to any particular heat resistance or bonding mechanism, thus possessing broader applicability and flexibility. In some embodiments, the first anti-plating layer 20 may also include inorganic fillers. The addition of inorganic fillers can further enhance the mechanical strength, hardness, dimensional stability, or impart other specific functions (e.g., thermal conductivity) of the first anti-plating layer 20.

[0156] Specifically, the inorganic filler can be selected from at least one group including graphite, carbon black, graphene, fullerene, silicon dioxide, aluminum oxide, aluminum hydroxide, calcium carbonate, magnesium carbonate, magnesium silicate, silicon carbide, titanium carbide, titanium oxide, aluminum hydroxide, magnesium oxide, calcium oxide, boron nitride, and aluminum nitride. These fillers not only enhance mechanical properties, but certain fillers (such as graphite, carbon black, and graphene) may also help absorb infrared laser energy due to their color or conductivity, thus assisting laser processing.

[0157] To improve the interfacial compatibility between inorganic fillers and the polymer resin matrix, prevent their aggregation at high content, and ensure effective bonding for stress transfer, the surfaces of these inorganic fillers undergo specific functional group modification. These functional groups are selected from at least one group consisting of aniline, alkyl, nitrogen-containing functional groups on the main chain or branches, double-bonded functional groups, and epoxy groups. These surface functional groups can react with or form strong interactions (such as hydrogen bonds) with active groups in the polymer resin (e.g., hydroxyl or epoxy groups), thereby tightly anchoring the inorganic filler to the resin matrix. Since the core function of the first anti-adhesion layer is to provide strong bonding and chemical resistance, the content of the inorganic filler is controlled at a low level (≤40%) to ensure that the polymer resin remains the main component and its core function is not affected.

[0158] At this time, in the first anti-coating layer 20, the weight percentage of the polymer resin (i.e., the sum of the high heat-resistant polymer and the hot melt adhesive) is between 60% and 100%, while the weight percentage of the inorganic filler is no more than 40% (i.e., 0% to 40%).

[0159] For polymer resins, the first anti-adhesion layer needs to form a very strong interlayer bond with the surface-treated (e.g., corona treatment) structural film layer. This strong bond mainly relies on the physical adsorption and / or chemical bonding between the polymer resin (especially the high heat-resistant polymer or reactive hot melt adhesive) and the surface of the structural film layer. Ensuring that the polymer resin content is not less than 60% is to guarantee that sufficient polymer molecules participate in the interfacial bonding, forming a continuous and strong adhesive interface, preventing interlayer delamination during use.

[0160] Meanwhile, the first anti-adhesive layer needs to withstand chemicals and heat that may be encountered during subsequent processing. High heat-resistant polymers (such as PI, PBO, epoxy-phenolic resins, etc.) are key to providing this resistance. Maintaining a high content of polymeric resins (≥60%), especially the content of high heat-resistant polymers, is fundamental to ensuring the chemical inertness and thermal stability of this layer.

[0161] In addition, polymer resin is the basis for film formation, and its content of not less than 60% helps to form a complete and defect-free continuous polymer network. This network can not only effectively encapsulate any inorganic fillers that may be added, but also form a dense physical barrier to resist the penetration of chemicals.

[0162] While inorganic fillers can improve mechanical properties, excessively high filler content (>40%) in the first anti-adhesive layer can have negative effects. A large number of filler particles will dilute the concentration of the polymer resin at the interface, reducing its effective contact area with the structural film and thus weakening interlayer adhesion. Simultaneously, excessively high filler content may also disrupt the continuity of the polymer matrix, reducing its overall chemical corrosion resistance.

[0163] Furthermore, a high content of inorganic fillers can significantly increase the rigidity of the material, but it may also make it brittle and more prone to cracking under stress, which is detrimental to the intermediate layer that needs to maintain a certain degree of flexibility.

[0164] Furthermore, this invention controls the peel performance of the second anti-adhesive layer from the substrate by using a high filler content. The first anti-adhesive layer, on the other hand, aims for the strongest adhesion to the structural film layer. Therefore, limiting the filler content in the first layer to a low level (≤40%) ensures that its function (strong adhesion, high stability) is not compromised, which contrasts sharply with the design of the second layer, which achieves easy peel through high filler content, and creates a functional gradient.

[0165] Therefore, setting the content of polymer resin in the first anti-adhesive layer to ≥60% and the content of inorganic filler to ≤40% is to ensure that the polymer resin, as the main component, can fully play its core role in strong adhesion and high chemical / thermal stability, forming a solid and reliable "underlayment". At the same time, it avoids the adverse effects of excessive filler content, such as decreased adhesion and increased brittleness, thus perfectly realizing the functional positioning of this layer in the overall composite film structure.

[0166] In some embodiments, the thickness of the first anti-adhesive layer 20 can be any value between 5 micrometers and 100 micrometers, such as 5 micrometers, 10 micrometers, 20 micrometers, 50 micrometers, 80 micrometers, 100 micrometers, etc.

[0167] The thickness of the first resist layer 20 is set between 5 micrometers and 100 micrometers. On the one hand, when the thickness of the first resist layer 20 is not less than 5 micrometers, it ensures that a complete, uniform, and pinhole-free continuous protective film is formed after coating and curing. This thickness is sufficient to resist the penetration and corrosion of strong acids, strong alkalis, and other chemicals in the subsequent PTH process, thereby providing a reliable chemical shield for the underlying copper conductors or functional areas and ensuring the effectiveness of the protection. On the other hand, when the thickness of the first resist layer 20 is not greater than 100 micrometers, its core "peelable" performance can be achieved. When it is necessary to remove the protective film, physical peeling can effectively separate the entire thickness of the first resist layer 20, allowing the substrate to fully detach, thereby achieving rapid and thorough peeling. If the thickness is too large, it may increase the difficulty of peeling or produce unnecessary residues. Therefore, this upper limit of thickness is the key to achieving efficient and non-destructive peeling while ensuring protective capabilities.

[0168] The second anti-adhesive layer 30 is a functional layer in the composite film structure that directly contacts the circuit board substrate to be protected. Its core functions are: on the one hand, to adhere firmly to the substrate surface during processing (such as bonding, drilling, and chemical treatment) and provide reliable protection; on the other hand, to be easily and cleanly peeled off from the substrate surface after all processes are completed, without leaving any adhesive residue.

[0169] To achieve the above functions, the material of the second anti-adhesive layer 30 is a hot melt adhesive with a special ratio or a composite material of hot melt adhesive and inorganic filler.

[0170] In one embodiment of the present invention, the hot melt adhesive is at least one of reactive polyurethane hot melt adhesive, polyamide hot melt adhesive, polyolefin hot melt adhesive, ethylene-vinyl acetate copolymer hot melt adhesive, polyethylene hot melt adhesive, and polypropylene hot melt adhesive. For the specific structural formula of the above hot melt adhesives, please refer to the foregoing embodiments, which will not be repeated here.

[0171] The hot melt adhesive plays a bonding role in this second anti-plating layer 30. Its main function is to utilize its "hot melt" property—that is, to soften, melt, and become sticky at a specific temperature (such as during hot pressing)—so that the entire composite anti-plating film can form an effective physical adhesion to the surface of the circuit board substrate (such as copper foil, epoxy resin, etc.). When cooled, the hot melt adhesive re-cures, thereby firmly fixing the composite anti-plating film to the area to be protected on the substrate, ensuring that it will not shift, warp, or fall off during subsequent processing such as drilling, chemical immersion, or electroplating.

[0172] In some embodiments, to ensure that the hot melt adhesive can sufficiently soften and flow during the bonding process (e.g., 70°C to 150°C) to achieve good wetting and adhesion, while maintaining sufficient cohesive strength at room temperature or slightly higher operating temperatures without creep or premature failure, the softening point of the hot melt adhesive is preferably not less than 40°C. Selecting a hot melt adhesive with a softening point not lower than 40°C ensures that the composite anti-coating film remains solid and dimensionally stable during storage, transportation, and non-heated processing steps, avoiding stickiness or deformation. Simultaneously, this softening point is below the typical lower limit of hot-press bonding temperature (70°C), ensuring smooth melting during bonding and achieving a tight bond with the substrate.

[0173] Furthermore, the inorganic filler ensures that the second anti-plating layer 30 adheres firmly to the surface of various substrates such as copper foil, epoxy resin, or glass after curing. Simultaneously, it increases the cross-linking density of the second anti-plating layer 30, enhancing its pressure resistance, heat resistance, and chemical resistance, ensuring that the second anti-plating layer 30 remains crack-free and does not peel off under harsh processes such as high temperature and high pressure. This is because the inorganic filler undergoes a cross-linking reaction during curing, forming stable chemical bonds to enhance adhesion to the substrate, and also improving the cohesive strength, hardness, and heat resistance of the entire second anti-plating layer 30.

[0174] In this application, to improve the interfacial compatibility between the inorganic filler and the hot melt adhesive matrix, prevent agglomeration at high content, and ensure effective bonding to transfer stress, the surface of the inorganic filler is modified with specific functional groups. Specifically, the surface of the inorganic filler is modified with one or more functional groups selected from the group consisting of aniline, alkyl, nitrogen-containing functional groups on the main chain or branches, double-bonded functional groups, and epoxy groups. These functional groups can react with or form strong interactions with active groups (such as hydroxyl or epoxy groups) in the hot melt adhesive, thereby tightly anchoring the inorganic filler in the hot melt adhesive matrix. This results in a protective layer with higher hardness, Young's modulus, and flexural modulus, effectively resisting impact and thermal stress during etching.

[0175] In some embodiments, the inorganic filler is selected from at least one of graphite, carbon black, graphene, fullerene, silicon dioxide, aluminum oxide, aluminum hydroxide, calcium carbonate, magnesium carbonate, magnesium silicate, silicon carbide, titanium carbide, titanium oxide, magnesium oxide, calcium oxide, boron nitride, and aluminum nitride. These fillers can significantly improve the mechanical properties of the second anti-coating layer 30 (such as hardness, Young's modulus, tensile modulus, and flexural modulus). Furthermore, certain fillers (such as graphite, carbon black, and graphene) may also help absorb infrared laser energy due to their color or conductivity, thus assisting laser processing.

[0176] In some key embodiments of the present invention, in order to achieve a balance between "strong adhesion" and "easy removal," the weight percentage of the hot melt adhesive in the second anti-adhesive layer 30 is set within a wide range, namely between 5% and 95%, for example, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, and 95%. Simultaneously, the weight percentage of the inorganic filler is also correspondingly between 5% and 95%, for example, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, and 95%.

[0177] Specifically, in the second anti-adhesive layer 30, even with a very high inorganic filler content (e.g., close to 95%), at least 5% by weight of hot melt adhesive is retained to ensure sufficient adhesive to form a continuous polymer matrix. This matrix not only effectively "bonds" a large number of inorganic filler particles together to form a film with a certain cohesive strength, but more importantly, it provides the polymer phase necessary for interfacial bonding with the circuit board substrate. If the hot melt adhesive content is less than 5%, it may result in the inability to form a continuous adhesive matrix, an overly loose and brittle film, or insufficient adhesion to the substrate to meet the protection requirements of the process.

[0178] Furthermore, this invention precisely controls the adhesion between the second anti-adhesive layer 30 and the substrate by using a high content of inorganic fillers. Setting the upper limit of the hot melt adhesive content to 95% means that the minimum allowable content of inorganic fillers can be as low as 5%. If the content of the hot melt adhesive is too high (e.g., exceeding 95%), the relative content of the inorganic fillers will be too low, and their physical regulating effect on the interfacial adhesion will become negligible. In this case, the adhesion of the layer is mainly determined by the properties of the hot melt adhesive itself, which may lead to excessively strong adhesion, making it difficult to achieve clean, residue-free peeling.

[0179] Therefore, by controlling the weight percentage of the hot melt adhesive within a wide range of 5% to 95%, the present invention can flexibly adjust its relative ratio with inorganic fillers to precisely customize the bonding strength of the second anti-plating layer 30 to different substrate materials, thereby achieving a final, controllable, clean and residue-free peeling effect while ensuring that the protective film adheres firmly during the processing.

[0180] In some embodiments, the thickness of the second anti-adhesive layer 30 can be any value between 5 micrometers and 100 micrometers, such as 5 micrometers, 10 micrometers, 20 micrometers, 50 micrometers, 80 micrometers, 100 micrometers, etc. Preferably, its thickness is between 5 micrometers and 20 micrometers. This thickness range ensures that there is sufficient material to form an effective bond with the substrate, while not being too thick to affect peel performance or increase costs.

[0181] In some embodiments, to facilitate the storage, transportation, and handling of the composite resist film before it is bonded to the circuit board, the composite resist film may further include a release layer 40. The release layer 40 is disposed on the side surface of the second resist layer 30 facing away from the first resist layer 20.

[0182] It is understandable that the core function of the release layer 40 is to serve as a temporary protective barrier. Since the exposed surface of the second anti-adhesive layer 30 has a certain degree of stickiness, the release layer 40 can effectively prevent them from sticking together during winding and storage, or from being contaminated by external dust and impurities, thereby ensuring that the second anti-adhesive layer 30 maintains its surface cleanliness and adhesive performance before use.

[0183] In one embodiment, to achieve the above functions, the substrate of the release layer 40 may be made of materials such as polyethylene terephthalate (PET), biaxially oriented polyester film (BOPET), oriented polypropylene (OPP), polyethylene (PE), or polyurethane (PU). To balance protective performance and material cost, the thickness of the release layer 40 may be any value between 9 micrometers and 75 micrometers, such as 9 micrometers, 10 micrometers, 20 micrometers, 30 micrometers, 40 micrometers, 50 micrometers, 70 micrometers, and 75 micrometers.

[0184] Furthermore, the release force between the release layer 40 and the second anti-adhesive layer 30 is a key parameter. In one embodiment, the release force can be any value between 5 g / cm and 500 g / cm, such as 5 g / cm, 50 g / cm, 100 g / cm, 200 g / cm, 300 g / cm, 400 g / cm, 500 g / cm, etc. This range ensures that the release layer 40 can be firmly attached to the surface of the second anti-adhesive layer 30 and will not accidentally fall off during normal handling, while also being easily and smoothly peeled off by the operator during use, without causing any tensile deformation or damage to the underlying second anti-adhesive layer 30 during the peeling process.

[0185] It is worth noting that in practical applications, the operator only needs to peel off and discard this release layer 40 before applying the composite anti-plating film to the circuit board.

[0186] It is understood that the composite anti-plating film of the present invention, by employing a second anti-plating adhesive layer 30 containing a hot melt adhesive, ensures excellent adhesion and chemical corrosion resistance, effectively resists the erosion of strong acid and alkali solutions, and withstands the harsh conditions of high temperature (e.g., 180°C) and high pressure (e.g., greater than 1.8MPa) in multilayer board lamination, providing stable protection for delicate circuits.

[0187] Meanwhile, the second anti-adhesive layer 30 uses hot melt adhesive as the base, so that the cured film layer can be peeled off, avoiding the damage to sensitive substrates (such as glass and ceramics) or high-density circuits caused by traditional strong acid and strong alkali peeling processes, thus improving process yield and product reliability.

[0188] Furthermore, by combining the second anti-plating layer 30 with the first anti-plating layer 20 and the structural film layer 10, a synergistic system with complementary functions is formed. The first anti-plating layer 20 serves as a functional layer, providing chemical protection and gentle peeling capability, while the structural film layer 10 serves as a skeleton layer, providing physical support for the second anti-plating layer 30. This effectively prevents defects such as orifice retraction caused by softening during the electroless metal plating process, and solves the process defect problem caused by insufficient structural strength of existing peelable materials. It achieves a comprehensive balance of excellent protective performance, gentle peeling capability, and structural stability.

[0189] In some embodiments, the first anti-coating layer 20 and / or the second anti-coating layer 30 further include a solvent selected from at least one of water, N-methylpyrrolidone, ethanol, acetone, ethyl acetate, n-butyl ether, methyl tert-butyl ether, dimethyl phthalate, butanone, dimethyl sulfoxide, n-butyl ketone, cyclohexanone, toluene, and xylene. The main function of the solvent is to dissolve the polymer resin, disperse the inorganic filler, and adjust the viscosity of the slurry to facilitate coating processing.

[0190] In some embodiments, the first anti-adhesive layer 20 and / or the second anti-adhesive layer 30 further include additives, said additives including at least one of leveling agents, dispersants, and defoamers. Examples of such additives include leveling agent BYK530, dispersant BYK2152, and defoamer BYK333.

[0191] In some embodiments, the solvent content in the first anti-coating layer 20 is 0 to 10 times the total weight of the polymer resin.

[0192] In the second anti-adhesive layer 30, the solvent content is 0 to 10 times the total weight of the hot melt adhesive.

[0193] The solvent content range mentioned above ensures that the composition has sufficient fluidity for coating, but does not result in excessively low solid content, film formation difficulties, or excessively long drying time due to excessive solvent content.

[0194] In some embodiments, the content of the additives in the first anti-adhesive layer 20 is 0.5% to 5% by weight of the total weight of the polymer resin.

[0195] In the second anti-adhesive layer 30, the content of the additives is 0.5% to 5% by weight of the total weight of the hot melt adhesive.

[0196] The above-mentioned content range of additives is intended to ensure that the additives can effectively play their role in improving process performance, while avoiding adverse effects on the core properties of the final film (such as adhesion and chemical resistance) due to excessive addition.

[0197] As can be seen from the above embodiments, the composite anti-coating film of this application has the following beneficial effects:

[0198] 1. Excellent chemical and pressure resistance: By using specific high heat-resistant polymers (such as epoxy-phenolic, PI, PBO, PBI, etc.) and optional inorganic fillers to form the first anti-plating layer, combined with a robust structural film layer, the composite film can effectively resist the erosion of strong acid and alkali solutions (such as chemical plating and desizing solutions) in PCB manufacturing processes, and can withstand the high temperature and high pressure conditions in processes such as multilayer board lamination, providing stable and reliable protection for delicate circuits.

[0199] 2. Gentle and convenient peeling characteristics: The second anti-adhesive layer uses a hot-melt adhesive, and in particular, the high content of inorganic fillers is used to precisely control its interfacial bonding force with the substrate. This allows the entire composite film to be completely and cleanly peeled off from the circuit board substrate by physical means (such as manually peeling off the structural film layer) after the protective function is completed. This avoids the damage to the substrate caused by traditional strong acid and strong alkali chemical stripping solutions, and also eliminates the need for specific wet film removal equipment.

[0200] 3. Excellent structural stability to prevent process defects: The presence of the structural film layer provides key physical support for the relatively soft anti-adhesive layer, effectively preventing the softening, shrinkage, and deformation of the peelable material due to insufficient strength during the process (such as when heated or impacted), or causing process defects such as "orifice retraction".

[0201] 4. Suppressing Drill Burrs: When the composite anti-plating film is applied to the substrate for drilling, its structural film layer and adhesive layer can provide effective support for the copper foil exit edge, which helps to suppress the generation of burrs and improve drilling quality.

[0202] 5. Achieving a comprehensive balance of performance: Through an ingenious multi-layer structure design (structural film layer / first anti-adhesive layer / second anti-adhesive layer) and the selection of functionally graded materials (especially by using the inorganic filler content gradient to control the adhesive force), the product successfully balances the often contradictory performance requirements of high protection (chemical resistance, pressure resistance, structural stability) and ease of use (gentle, convenient, and residue-free peeling) in a single product.

[0203] This invention also provides a method for preparing an anti-plating material. This method is used to prepare a first anti-plating material (for forming a first anti-plating adhesive layer) and / or a second anti-plating material (for forming a second anti-plating adhesive layer) constituting the aforementioned composite anti-plating film. The specific steps of this method for preparing the anti-plating material are described in the following embodiments. Since this preparation method adopts all the technical solutions of all the above embodiments, it possesses at least all the beneficial effects brought about by the technical solutions of the above embodiments, and will not be repeated here.

[0204] like Figure 2 As shown, in some embodiments, the preparation method includes the following steps:

[0205] S1. Preparation of resin slurry: The resin components constituting the first anti-plating material or the second anti-plating material are mixed in a first solvent to obtain a resin slurry.

[0206] This step aims to pre-dissolve or disperse the desired polymeric resin components in a solvent to form a homogeneous liquid phase base. Specifically, when preparing the resin slurry for the first anti-plating material, the resin components include at least one of a high heat-resistant polymer (such as epoxy-phenolic composite resin, polyimide, etc.) with a main chain containing aromatic rings and / or heterocyclic rings as defined in the foregoing embodiments and a hot-melt adhesive. When preparing the resin slurry for the second anti-plating material, the resin components include the hot-melt adhesive as defined in the foregoing embodiments.

[0207] The first solvent used may be selected from at least one of water, N-methylpyrrolidone, ethanol, acetone, ethyl acetate, n-butyl ether, methyl tert-butyl ether, dimethyl phthalate, butanone, dimethyl sulfoxide, n-butyl ketone, cyclohexanone, toluene, and xylene, and the selection is mainly based on its ability to dissolve or disperse the resin components used.

[0208] In some embodiments, to improve the mixing effect in subsequent steps, at least one additive selected from dispersants, defoamers, and leveling agents may be pre-added to the first solvent before adding the resin components. For example, a dispersant (such as BYK 2152) may be pre-added to help the resin disperse better, an defoamer (such as BYK 333) may be added to reduce bubbles generated during stirring, and a leveling agent (such as BYK 530) may be added to improve the surface smoothness of the final coating.

[0209] In some embodiments, the total amount of additives may be 0.5% to 5% of the total weight of the resin components.

[0210] In some embodiments, the mixing process for preparing the resin slurry can be achieved using high-speed mixing equipment (such as a homogenizer, emulsifier, high-speed mixer, or collider).

[0211] In some embodiments, in order to ensure that the resin is fully dissolved or dispersed, and to avoid premature reaction or degradation of the resin due to high-speed shear heat generation, the mixing process is preferably carried out under specific conditions: the mixing speed is between 3600 rpm and 7200 rpm, the slurry temperature is controlled at no higher than 45°C by means of cooling water jackets or the like, and the duration is between 20 minutes and 50 minutes (e.g., 30 minutes).

[0212] The settings for rotation speed, temperature, and time are as follows: a rotation speed of 3600 to 7200 rpm provides sufficient shear force to disperse resin particles. If the rotation speed is too low (e.g., below 3600 rpm), insufficient mixing may lead to phase separation. A temperature not exceeding 45°C is to avoid resin pre-crosslinking; above 45°C, the hot melt adhesive is prone to premature reaction, shortening the shelf life. A duration of 20 to 50 minutes is to balance efficiency and thoroughness. A duration shorter than 20 minutes may result in uneven dispersion of the slurry, while a duration longer than 50 minutes increases energy consumption without providing additional benefit. By controlling these parameters, the viscosity of the resin slurry is ensured to be appropriate, laying the foundation for subsequent filler integration.

[0213] S2. Preparation of filler slurry: The surface-modified inorganic filler is mixed in a second solvent to obtain the filler slurry.

[0214] This step aims to fully wet and uniformly disperse the inorganic filler particles in the solvent, breaking down any potential agglomerates and forming a stable suspension. Specifically, inorganic fillers (such as silica, alumina, etc.) whose surfaces have been modified with specific functional groups (such as aniline, alkyl, nitrogen-containing functional groups, double-bond functional groups, epoxy groups, etc.) as defined in the previous embodiments are added to the second solvent for mixing.

[0215] Similar to the preparation of resin slurries, in some embodiments, at least one additive selected from dispersants, defoamers and leveling agents may be pre-added to the second solvent before the inorganic filler is added, in order to improve the dispersion efficiency and stability of the filler.

[0216] The process can employ similar equipment and process parameters as step S1, for example, using a homogenizer at a speed of 3600 rpm to 7200 rpm and a temperature not exceeding 45°C for a duration of 20 to 50 minutes, such as 30 minutes, to ensure that the inorganic filler particles are fully wetted and uniformly dispersed to form a non-agglomerated filler slurry (also known as slurry B).

[0217] It is worth noting that the first solvent and the second solvent can be the same or different. Specifically, the first solvent and the second solvent are selected from at least one of water, N-methylpyrrolidone, ethanol, acetone, ethyl acetate, n-butyl ether, methyl tert-butyl ether, dimethyl phthalate, butanone, dimethyl sulfoxide, n-butyl ketone, cyclohexanone, toluene, and xylene.

[0218] S3. Mixing: The filler slurry is added to the resin slurry being stirred to obtain the first anti-plating material or the second anti-plating material in ink form.

[0219] This step is crucial for achieving a uniform composite of the organic resin matrix and the inorganic filler. Specifically, the filler slurry prepared in step S2 is slowly, in batches, or continuously added to the resin slurry prepared in step S1 while the mixture is being stirred. Slow addition is necessary to avoid excessively high local filler concentrations that could lead to re-agglomeration. After addition, thorough mixing continues to ensure that the inorganic filler particles achieve a uniform and stable dispersion in the final resin matrix.

[0220] In some embodiments, the preferred process conditions for this final mixing step are: a mixing speed between 3600 rpm and 7200 rpm, a slurry temperature not exceeding 45°C, and a duration between 60 minutes and 120 minutes (e.g., 90 minutes). The relatively extended mixing time is to ensure that the two premixed slurries are thoroughly and uniformly mixed, and that the inorganic filler is fully penetrated into the resin network.

[0221] Through the above steps, a first and a second resist material in ink or paste form, suitable for subsequent coating processes, can be obtained. This preparation method effectively ensures the uniformity, stability, and processing applicability of the final resist material through stepwise premixing, the rational use of additives, and precise control of mixing process conditions.

[0222] The present invention also provides a method for preparing a composite anti-coating film, which is used to prepare the composite anti-coating film described in any of the foregoing embodiments.

[0223] The method for preparing this composite anti-plating film aims to combine the aforementioned first and second anti-plating materials with the structural film layer through precisely controlled coating and curing steps to form a composite thin film product with a specific multilayer structure.

[0224] like Figure 3 As shown, in one embodiment, the preparation method specifically includes the following steps:

[0225] S10. Providing a structural film layer: First, the structural film layer described in the foregoing embodiments is provided. For example, it may be a roll of polyimide (PI) film with a specific thickness (e.g., 50 micrometers) or other suitable substrate film.

[0226] S20. Coating the first anti-plating material and performing a first curing treatment: The prepared first anti-plating material, which is in the form of ink or paste, is uniformly coated onto one side surface of the structural film layer using coating techniques such as doctor blade coating, roller coating, or screen printing to form a wet film of a predetermined thickness. The first anti-plating material comprises, as defined in the preceding embodiments, at least one of a high heat-resistant polymer with a main chain containing aromatic rings and / or heterocyclic rings and a hot-melt adhesive, and optionally includes inorganic fillers. Subsequently, the structural film layer coated with the first anti-plating material undergoes a first curing treatment to form a solid first anti-plating adhesive layer.

[0227] In one embodiment, the first curing process is specifically a drying process. The drying process allows for the rapid evaporation of the solvent through heating, and initiates or accelerates any cross-linking reactions that may exist in the material (e.g., epoxy-phenolic systems), thereby forming a solid film with sufficient cohesive strength and adhesion. To ensure effective curing, the drying process is preferably performed under specific conditions: a temperature between 50°C and 150°C, and a time between 30 seconds and 1.5 hours (i.e., 90 minutes). This temperature and time range is designed to ensure effective solvent removal and induce sufficient curing, while avoiding thermal damage or over-curing of the material.

[0228] In some embodiments, the thickness of the first resist layer can be controlled between 1 micrometer and 100 micrometers by controlling the coating amount and curing conditions. In a preferred embodiment, as a "base coat", the thickness of the first resist layer can be controlled between 3 micrometers and 10 micrometers to achieve thinning while ensuring adhesion.

[0229] In some embodiments, before coating the first anti-plating material onto the structural film layer, the preparation method of this application further includes:

[0230] Surface modification treatment of the structural film layer: Before applying the first anti-plating material to the structural film layer, at least one surface of the structural film layer to which the anti-plating material will be applied is subjected to surface modification treatment. The core purpose of this treatment is to increase the surface energy of the structural film layer, that is, to increase its surface dyne value, thereby ensuring that the subsequently applied first anti-plating adhesive layer can form a strong and reliable interlayer bond with it.

[0231] In one embodiment, the surface modification treatment can be corona treatment, i.e., bombarding and activating the surface of the structural film layer with plasma generated by high-voltage discharge. Of course, other effective surface modification techniques such as plasma treatment or flame treatment can also be used. By implementing this surface modification treatment, the dyne value of the surface of the structural film layer to be coated is increased to not less than 30, thereby providing a bonding interface with high affinity for subsequent coatings. In a preferred embodiment, the surface dyne value of the structural film layer can be increased to not less than 54 to obtain even better interlayer bonding strength.

[0232] S30. Coating a second anti-plating material and performing a second curing treatment: The prepared second anti-plating material, in the form of ink or paste, is uniformly coated onto the surface of the first anti-plating adhesive layer formed in step S20 on the side opposite to the structural film layer, forming another wet film of a predetermined thickness. The composition of the second anti-plating material is as defined in the previous embodiments, including a hot melt adhesive and typically containing a high content of surface-modified inorganic fillers. Subsequently, the composite film coated with the second anti-plating material is subjected to a second curing treatment to form a solid second anti-plating adhesive layer.

[0233] Similar to the first curing treatment, the second curing treatment is preferably a drying treatment, and its process conditions can also be set as follows: temperature between 50 degrees Celsius and 150 degrees Celsius, and time between 30 seconds and 1.5 hours (i.e. 90 minutes).

[0234] In some embodiments, the thickness of the second resist layer can be controlled between 1 micrometer and 100 micrometers by controlling the coating amount and curing conditions. In a preferred embodiment, the thickness of the "adhesive layer" in contact with the substrate can be controlled between 5 micrometers and 20 micrometers.

[0235] S40. Setting a release layer: After the second resist-plating layer is formed, in order to facilitate the winding, storage, transportation, and subsequent pre-use operations of the final product, a release layer (or release film) can be attached to the surface of the second resist-plating layer facing away from the first resist-plating layer. This release layer is used to protect the surface of the second resist-plating layer, which has a certain degree of adhesion, and prevent it from being contaminated or becoming self-adhesive.

[0236] Specifically, the substrate of the release layer can be at least one of the following materials: PET, BOPET, OPP, PE and PU, and its thickness can be between 9 micrometers and 75 micrometers.

[0237] Furthermore, the release force between the release layer and the second anti-adhesive layer is a key parameter, preferably between 5 g / cm and 500 g / cm. This range ensures that the release layer adheres firmly but can also be easily and smoothly removed during use without damaging the underlying adhesive layer.

[0238] Through the above steps, the multilayer composite anti-coating film product of this invention can be obtained. The preparation method has a clear process flow, and by precisely controlling the coating and curing conditions of each layer, a composite anti-coating film with complete structure and excellent performance can be stably produced.

[0239] The present invention also provides a method for manufacturing a circuit board, wherein the composite anti-plating film described in any of the preceding claims is used as a high-performance temporary protective material, and is particularly suitable for circuit board manufacturing processes that include drilling and hole metallization steps.

[0240] like Figure 4 As shown, in one embodiment, the method for manufacturing the circuit board may specifically include the following steps:

[0241] S110. Providing a circuit board substrate: First, a circuit board substrate to be processed is provided. This substrate can be a rigid FR-4 copper-clad laminate, a flexible polyimide (PI) substrate, or other insulating substrate suitable for fabricating a circuit board. On this circuit board substrate, areas to be drilled are pre-defined according to the circuit design. These areas may be covered with copper foil or other conductive metal structures, or they may be exposed insulating substrate surfaces.

[0242] S120. Applying the anti-plating film: The composite anti-plating film described in any of the preceding embodiments is adhered to the surface of the circuit board substrate, ensuring that it covers the predetermined drilling area and other areas that need to be protected (areas to be protected). During adhesion, it is necessary to ensure that the second anti-plating adhesive layer of the composite anti-plating film (i.e., the layer containing a high proportion of inorganic fillers and having controllable adhesion) is in direct contact with the surface of the circuit board substrate.

[0243] In a preferred embodiment, the bonding step can be performed under specific process conditions: a temperature between 70°C and 150°C, a pressure between 0.1 MPa and 9 MPa, hot-pressing the composite anti-plating film onto the surface of the circuit board substrate for 5 seconds to 30 minutes to ensure that a tight, bubble-free bond is formed between the composite anti-plating film and the substrate.

[0244] It is worth noting that, depending on the circuit board design, the composite anti-plating film can be applied to only one side of the substrate, or it can be applied to both sides of the substrate simultaneously.

[0245] S130. Drilling: For a circuit board substrate with the composite resist film already applied, drilling is performed in the predetermined drilling area to form a hole structure that penetrates the substrate or reaches a specific depth. Drilling can be performed using methods such as mechanical drilling or laser drilling. In this step, because the composite resist film (especially its structural film layer with a certain strength and toughness) covers the surface of the drilling area, it can provide effective mechanical support for the edge of the drill bit penetrating the copper foil (if present). This helps to suppress burrs or spikes caused by the ductility of the metal, thereby obtaining a cleaner and more regular drilling quality.

[0246] S140. Copper Plating: Copper plating is performed on the circuit board substrate after drilling. The purpose of this treatment is to form a conductive copper layer on the inner wall of the hole structure to achieve electrical interconnection between different levels of circuitry (e.g., PTH process). If necessary, copper plating can also be performed simultaneously on areas of the substrate surface not covered by the composite resist coating (areas to be plated with copper) to form new circuit patterns or thicken existing circuitry. Copper plating typically includes a series of chemical pretreatments (such as degreasing, micro-etching, activation, etc.) followed by chemical copper plating and / or electrolytic copper plating steps. Throughout the copper plating process, the composite resist coating, with its excellent chemical resistance, protects the areas it covers (areas to be protected) from being plated with copper.

[0247] S150, Film Removal: After completing all necessary copper plating and subsequent processing steps, the composite resist film is removed. Specifically, the exposed structural film layer of the composite resist film is grasped and lifted using physical methods (e.g., manual peeling). Because the structural film layer has a strong bond with the first resist layer, and the first and second resist layers are also bonded together, sufficient mechanical force is generated when the structural film layer is peeled off, causing the underlying first and second resist layers to detach completely from the protected area of ​​the circuit board substrate as a whole. Thanks to the controlled adhesion between the second resist layer and the substrate, this peeling process is typically clean and residue-free. This purely physical film removal method is simple, efficient, and avoids the damage or contamination risks that may arise from chemical stripping solutions.

[0248] Through the above steps, the composite anti-plating film of the present invention can be used to achieve effective temporary protection of specific areas in the circuit board manufacturing process including drilling, and finally obtain a circuit board with a metallized hole structure.

[0249] The present invention also provides another method for manufacturing a circuit board, which also uses the composite anti-plating film described in any of the foregoing embodiments as a high-performance temporary protective material, and is particularly suitable for circuit board manufacturing processes that perform patterned metal deposition by selective windowing (e.g., laser ablation).

[0250] like Figure 5As shown, in another embodiment, the method for manufacturing the circuit board may specifically include the following steps:

[0251] S210. Providing a circuit board substrate: First, a circuit board substrate to be processed is provided. This substrate can be a rigid or flexible substrate. On the circuit board substrate, areas that need to be copper-plated or otherwise metallized are predefined according to the circuit design, i.e., areas to be copper-plated. These areas to be copper-plated can be exposed insulating substrate surfaces or pre-formed metallic conductive structures on the substrate (such as lines or pads that need to be thickened).

[0252] S220. Applying the anti-plating film: The composite anti-plating film described in any of the foregoing embodiments is adhered to the surface of the circuit board substrate, ensuring that it at least covers the predetermined copper plating area and other areas requiring protection. During adhesion, it is also necessary to ensure that the second anti-plating adhesive layer of the composite anti-plating film is in direct contact with the surface of the circuit board substrate.

[0253] In one embodiment, the bonding step can be performed under specific process conditions: a temperature between 70°C and 150°C, and a pressure between 0.1 MPa and 9 MPa, wherein the composite anti-plating film is hot-pressed onto the surface of the circuit board substrate for 5 seconds to 30 minutes to ensure a tight bond. In a specific, non-limiting example, the bonding parameters could be a temperature of 120°C for 30 seconds and a pressure of 0.6 MPa.

[0254] S230, Windowing: For a circuit board substrate with the composite resist film already attached, selectively remove a local area of ​​the composite resist film corresponding to the predetermined copper plating area, so as to form at least one precise opening (window) on the composite resist film, thereby exposing the copper plating area to be metallized below the opening.

[0255] In a preferred embodiment, the windowing step is achieved by laser ablation. A high-energy laser beam is used to precisely ablate and remove the composite anti-coating material in a designated area, forming an opening with sharp edges.

[0256] In some embodiments, after laser ablation to create windows, the method for fabricating the circuit board of this application further includes: pickling: After laser ablation to create windows, in order to remove any adhesive residue or other ablation products that may remain on the edge of the opening or the exposed substrate surface, it is preferable to perform a pickling treatment on the substrate before metallization. In a specific example, this pickling can be performed using a mixed solution containing 30% sulfuric acid and 10% hydrogen peroxide to effectively clean the windowed area and ensure the quality and adhesion of subsequent metal deposition. Furthermore, after pickling, a water wash is typically performed to remove residual acid.

[0257] S240, Metallization: Metallization is performed on the areas exposed within the opening after windowing (and optional pickling) to be plated with copper. This process aims to selectively deposit a metal layer (typically copper) within the area defined by the opening. The metallization process may include electroless plating and / or electroplating steps. For example, electroless copper plating can be performed first to form a conductive underlayer, followed by electrolytic copper plating to thicken to the desired thickness. Throughout the metallization process, any remaining composite resist film continues to provide protection, preventing metal deposition on its surface. After the metallization process is completed, a rinsing step is typically performed to remove any residual plating solution.

[0258] S250, Film Removal: After completing all necessary metallization and subsequent processing steps, the composite resist film is removed. Similar to the first method, the specific operation involves physically grasping and lifting the exposed structural film layer of the composite resist film (e.g., manually peeling it off). The structural film layer will cause the underlying first and second resist layers to detach from the circuit board substrate surface as a whole. Due to the precise control of the adhesion between the second resist layer and the substrate, this peeling process is also clean and residue-free.

[0259] Through the above steps, the composite anti-plating film of this invention can be used to achieve patterned metal deposition in a circuit board manufacturing process that includes selective windowing, ultimately obtaining a circuit board with the desired circuit pattern. This method is particularly suitable for applications involving the fabrication of fine lines or selective area thickening.

[0260] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A composite anti-coating film, characterized in that, include: Structural membranes; A first anti-adhesive layer is disposed on one side of the structural film layer; The second anti-adhesive layer is disposed on the side of the first anti-adhesive layer that faces away from the structural film layer; The material of the first anti-adhesive layer includes a polymer resin, which includes at least one of a high heat-resistant polymer with aromatic rings and / or heterocyclic rings in the main chain and a hot melt adhesive. The material of the second anti-adhesive layer includes a hot melt adhesive or a composite material of a hot melt adhesive and an inorganic filler, wherein the surface of the inorganic filler is modified with at least one functional group selected from the group consisting of aniline, alkyl, nitrogen-containing functional groups on the main chain or branches, double-bonded functional groups and epoxy groups.

2. The composite anti-coating film as described in claim 1, characterized in that, The material of the structural membrane is selected from at least one of the following groups: polyethylene terephthalate, polyethylene naphthalate, polyetherimide, polyphenylene sulfide, ethylene-vinyl acetate copolymer, polyvinyl butyral, polyether ether ketone, nylon, polycarbonate, poly(p-phenylenebenzodioxazole), polyimide, polysulfone, polyphenylene sulfone, liquid crystal polymer, polymethylpentene, polyethylene succinate, polytetrahydrofuran ether glycol, cyclic olefin copolymers, polypropylene-polyethylene-rubber copolymers, polyurethane copolymers, and rubber-polypropylene-polyethylene copolymers.

3. The composite anti-coating film as described in claim 1, characterized in that, The thickness of the structural membrane layer is between 9 micrometers and 500 micrometers.

4. The composite anti-coating film as described in claim 1, characterized in that, On the side where the structural film layer and the first anti-adhesive layer meet, the dyne value of the surface of the structural film layer is not less than 30.

5. The composite anti-coating film as described in claim 1, characterized in that, The softening point of the hot melt adhesive is not less than 40°C.

6. The composite anti-coating film as described in claim 1, characterized in that, The heat-resistant polymer whose main chain contains aromatic rings and / or heterocycles is selected from at least one of the group consisting of epoxy-phenolic composite resins, polyimides, poly(p-phenylenebenzodioxazole) and polybenzimidazole.

7. The composite anti-coating film as described in claim 6, characterized in that, The epoxy resin is selected from at least one of glycidylamine epoxy resin, polyfunctional o-cresol glycidyl ether epoxy resin, phenol biphenyl epoxy resin, bisphenol F solid epoxy resin, isocyanate modified epoxy resin, naphthol epoxy resin, and phenol phenolic epoxy resin.

8. The composite anti-coating film as described in claim 7, characterized in that, The phenolic resin is selected from at least one of linear phenol-formaldehyde resin and linear BPA-formaldehyde resin.

9. The composite anti-coating film as described in claim 6, characterized in that, In the epoxy-phenolic composite resin, the content of phenolic resin and the content of epoxy resin satisfy the following formula: Phenolic resin content = (hydroxyl equivalent of phenolic resin / epoxy equivalent of epoxy resin) × epoxy resin content.

10. The composite anti-coating film as described in claim 1, characterized in that, The thickness of the first anti-coating layer is between 5 micrometers and 100 micrometers; and / or The thickness of the second anti-coating layer is 5 micrometers to 100 micrometers.

11. The composite anti-coating film as described in claim 1, characterized in that, The hot melt adhesive is selected from at least one of the group consisting of reactive polyurethane hot melt adhesives, polyamide hot melt adhesives, polyolefin hot melt adhesives, ethylene-vinyl acetate copolymer hot melt adhesives, polyethylene hot melt adhesives, and polypropylene hot melt adhesives.

12. The composite anti-coating film as described in claim 1, characterized in that, The first anti-coating layer also includes the inorganic filler.

13. The composite anti-coating film as described in claim 12, characterized in that, In the first anti-coating layer, the weight percentage of the polymer resin is between 60% and 100%, and the weight percentage of the inorganic filler is no more than 40%.

14. The composite anti-coating film as described in claim 12, characterized in that, The weight percentage of the inorganic filler in the second anti-plating layer is higher than the weight percentage of the inorganic filler in the first anti-plating layer.

15. The composite anti-coating film as described in claim 12, characterized in that, In the second anti-coating layer, the weight percentage of the hot melt adhesive is between 5% and 95%, and the weight percentage of the inorganic filler is between 5% and 95%.

16. The composite anti-coating film as described in claim 1, characterized in that, The inorganic filler is selected from at least one of the group consisting of graphite, carbon black, graphene, fullerene, silicon dioxide, aluminum oxide, aluminum hydroxide, calcium carbonate, magnesium carbonate, magnesium silicate, silicon carbide, titanium carbide, titanium oxide, aluminum hydroxide, magnesium oxide, calcium oxide, boron nitride, and aluminum nitride.

17. The composite anti-coating film according to any one of claims 1 to 16, characterized in that, The composite anti-plating film also includes a release layer, which is disposed on the side of the second anti-plating adhesive layer opposite to the first anti-plating adhesive layer.

18. The composite anti-coating film as described in claim 17, characterized in that, The thickness of the release layer is between 9 micrometers and 75 micrometers; and / or The release force of the release layer is between 5 g / cm and 500 g / cm.

19. The composite anti-coating film according to any one of claims 1 to 16, characterized in that, The first anti-plating layer and / or the second anti-plating layer further include a solvent selected from at least one of water, N-methylpyrrolidone, ethanol, acetone, ethyl acetate, n-butyl ether, methyl tert-butyl ether, dimethyl phthalate, butanone, dimethyl sulfoxide, n-butyl ketone, cyclohexanone, toluene, and xylene.

20. The composite anti-coating film as described in claim 19, characterized in that, The first anti-coating layer and / or the second anti-coating layer further include additives, which include at least one of leveling agents, dispersants, and defoamers.

21. The composite anti-coating film as described in claim 20, characterized in that, In the first anti-coating layer, the solvent content is 0 to 10 times the total weight of the polymer resin; and / or In the second anti-adhesive layer, the solvent content is 0 to 10 times the total weight of the hot melt adhesive; In the first anti-coating layer, the content of the additive is 0.5% to 5% by weight of the total weight of the polymer resin; In the second anti-coating layer, the content of the additive is 0.5% to 5% by weight of the total weight of the hot melt adhesive.

22. A method for preparing an anti-plating material, used to prepare a first anti-plating material and a second anti-plating material, characterized in that, The preparation method of the anti-plating material includes the following steps: Preparation of resin slurry: The resin components constituting the first anti-plating material or the second anti-plating material are mixed in a first solvent to obtain a resin slurry, wherein the resin component constituting the first anti-plating material includes at least one of a high heat-resistant polymer with aromatic rings and / or heterocycles in the main chain and a hot melt adhesive, and the resin component constituting the second anti-plating material includes a hot melt adhesive. Preparation of filler slurry: Surface-modified inorganic fillers are mixed in a second solvent to obtain a filler slurry; and Mixing: The filler slurry is added to the resin slurry being stirred to obtain the first anti-plating material or the second anti-plating material in ink form.

23. The method for preparing the anti-plating material as described in claim 22, characterized in that, In preparing the resin slurry, the method further includes pre-dissolving at least one additive selected from dispersants, defoamers, and leveling agents into the first solvent; and / or In preparing the filler slurry, at least one additive selected from dispersants, defoamers and leveling agents is pre-dissolved in the second solvent.

24. The method for preparing the anti-plating material as described in claim 22, characterized in that, In the step of preparing the first anti-plating material and / or the second anti-plating material, the mixing conditions include at least one of the following: The mixing speed for preparing the resin slurry is between 3600 rpm and 7200 rpm, the slurry temperature is not higher than 45°C, and the duration is between 20 minutes and 50 minutes. When preparing the filler slurry, the mixing speed is between 3600 rpm and 7200 rpm, the slurry temperature is not higher than 45°C, and the duration is between 20 minutes and 50 minutes. When mixing the filler slurry with the resin slurry, the mixing speed is between 3600 rpm and 7200 rpm, the slurry temperature is not higher than 45°C, and the duration is between 60 minutes and 120 minutes.

25. The method for preparing the anti-plating material as described in claim 22, characterized in that, The total weight of the first solvent and / or the second solvent is 0 to 10 times the total weight of the resin components; and / or The total weight of the additives is 0.5% to 5% of the total weight of the resin components.

26. A method for preparing a composite anti-coating film, characterized in that, Includes the following steps: Provide structural membranes; A first anti-plating material is applied to one side surface of the structural film layer and a first curing treatment is performed to form the first anti-plating adhesive layer, wherein the first anti-plating material comprises at least one of a high heat-resistant polymer with aromatic rings and / or heterocycles in the main chain and a hot melt adhesive. A second anti-plating material is applied to the side of the first anti-plating adhesive layer facing away from the structural film layer, and a second curing treatment is performed to form the second anti-plating adhesive layer. The second anti-plating material includes a hot melt adhesive or a composite material of a hot melt adhesive and an inorganic filler.

27. The method for preparing the composite anti-coating film as described in claim 26, characterized in that, Before coating the first anti-plating material onto the structural film layer, the preparation method further includes: The surface of the structural film layer bonded to the first anti-adhesive layer is subjected to surface modification treatment so that the dyne value of the surface of the structural film layer bonded to the first anti-adhesive layer is not less than 30.

28. The method for preparing the composite anti-coating film as described in claim 26, characterized in that, The first curing process and / or the second curing process include: Drying is carried out for 30 seconds to 90 minutes within a temperature range of 50 degrees Celsius to 150 degrees Celsius.

29. The method for preparing the composite anti-coating film as described in claim 26, characterized in that, The thickness of the first anti-coating layer is between 1 micrometer and 100 micrometers; and / or The thickness of the second anti-coating layer is between 1 micrometer and 100 micrometers.

30. The method for preparing the composite anti-coating film as described in claim 29, characterized in that, The thickness of the first anti-coating layer is between 3 micrometers and 10 micrometers; and / or The thickness of the second anti-coating layer is between 5 micrometers and 20 micrometers.

31. The method for preparing the composite anti-coating film as described in claim 26, characterized in that, The preparation method further includes: A release layer is provided on the side of the second anti-coating layer that faces away from the first anti-coating layer.

32. The method for preparing the composite anti-coating film as described in claim 31, characterized in that, The thickness of the release layer is between 9 micrometers and 75 micrometers; and / or The release force of the release layer is between 5 g / cm and 500 g / cm.

33. A method for manufacturing a circuit board, characterized in that, include: Provided circuit board: Provided circuit board substrate, wherein the circuit board substrate defines an area to be drilled; Applying an anti-plating film: The composite anti-plating film as described in any one of claims 1 to 21 is adhered to the circuit board substrate and covers the area to be drilled, wherein the second anti-plating adhesive layer of the composite anti-plating film is in contact with the circuit board substrate; Drilling: Drilling holes in the circuit board substrate to which the composite anti-coating film is attached, so as to form a hole structure in the area to be drilled; Copper plating: Copper plating is performed on the circuit board substrate and / or the inner walls of the hole structure; and Film removal: Remove the structural film layer of the composite anti-plating film, and detach the first anti-plating layer and the second anti-plating layer from the circuit board substrate.

34. The circuit board manufacturing method according to claim 33, characterized in that, The conditions for attaching the anti-plating film to the surface of the circuit board substrate include: The composite anti-coating film is hot-pressed onto the circuit board substrate at a temperature range of 70°C to 150°C and a pressure of 0.1 MPa to 9 MPa for 5 seconds to 30 minutes.

35. The circuit board manufacturing method according to claim 33, characterized in that, The area to be drilled is provided with a conductive metal structure; and / or The composite anti-plating film is adhered to one or both sides of the circuit board substrate.

36. A method for manufacturing a circuit board, characterized in that, include: Provide circuit board: Provide circuit board substrate, wherein a copper plating area is defined on the circuit board substrate; Applying an anti-plating film: The composite anti-plating film as described in any one of claims 1 to 21 is adhered to the circuit board substrate and covers the copper area to be plated, wherein the second anti-plating adhesive layer of the composite anti-plating film is in contact with the circuit board substrate; Opening a window: removing a local area of ​​the composite resist film corresponding to the copper area to be plated, so as to form at least one opening in the composite resist film and expose the copper area to be plated below the opening; Metallization treatment: Metallizing the exposed copper-to-be-plated area within the opening; and Film removal: Remove the structural film layer of the composite anti-plating film, and detach the first anti-plating layer and the second anti-plating layer from the circuit board substrate.

37. The circuit board manufacturing method according to claim 36, characterized in that, The area to be plated with copper is provided with a metal conductive structure.

38. The circuit board manufacturing method according to claim 36, characterized in that, The conditions for attaching the composite anti-plating film to the circuit board substrate include: The composite anti-coating film is hot-pressed onto the circuit board substrate at a temperature range of 70°C to 150°C and a pressure of 0.1 MPa to 9 MPa for 5 seconds to 30 minutes.

39. The circuit board manufacturing method according to claim 36, characterized in that, The composite anti-plating film is removed from the local area corresponding to the copper area to be plated by laser ablation.

40. The circuit board manufacturing method according to claim 39, characterized in that, Before metallizing the surface of the substrate, the circuit board fabrication method further includes: Pickling: The substrate is subjected to pickling treatment to remove adhesive residue generated by the laser ablation.

41. The circuit board manufacturing method according to claim 40, characterized in that, The pickling is carried out using a mixed solution containing 30% sulfuric acid and 10% hydrogen peroxide.

42. A circuit board, characterized in that, The circuit board is manufactured using the circuit board manufacturing method described in any one of claims 33 to 41.

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