An hvlp4 electronic copper foil and a method for manufacturing the same

Abstract

The application discloses an HVLP4 electronic copper foil and a preparation method thereof, and belongs to the technical field of electronic copper foils. In view of the technical problem that electronic copper foils in the prior art are difficult to simultaneously meet the requirements of ultra-low roughness and high peeling strength, the application provides an HVLP4 electronic copper foil, which comprises a copper foil base body and a gradient nano-tumorization layer, a multicomponent alloy layer, an oxidation-resistant layer and a composite coupling agent layer formed on the rough surface in sequence. The preparation method of the copper foil comprises S1 electrolytic original foil, S2 gradient tumorization treatment, S3 multicomponent alloy layer treatment, S4 oxidation-resistant treatment and S5 composite coupling agent coating. Through the synergistic effect of physical anchoring of the gradient nano-tumorization structure, thermal diffusion blocking of the multicomponent alloy layer and chemical bonding of the composite coupling agent, the peeling strength of the PPO substrate is greater than or equal to 0.45 N / mm under the condition that the roughness Rz of the rough surface is less than or equal to 0.7 microns, the balance between ultra-low roughness and high peeling strength is achieved, and the application is suitable for high-frequency and high-speed scenes such as 5G / 6G communication and AI servers.

Description

Technical Field

[0001] This invention belongs to the technical field of electronic copper foil processing methods, and particularly relates to an HVLP4 electronic copper foil and its preparation method. Background Technology

[0002] In today's era of rapid technological advancement, electronic devices are constantly moving towards miniaturization and high performance, and printed circuit boards (PCBs), as core components of electronic products, play an increasingly important role. The global PCB industry's demand for more sophisticated PCB materials continues to rise, driving future electronic copper foil products towards higher-end directions such as high speed and high frequency, high heat resistance, thinness, and high density. Electrolytic copper foil is one of the key raw materials for manufacturing printed circuit boards (PCBs), serving the function of signal transmission and is hailed as the neural network of electronic products.

[0003] High-frequency, high-speed PCBs possess characteristics such as high-speed transmission, low loss, low noise, and high precision, meeting the signal integrity and electromagnetic compatibility requirements of high-speed digital circuits, and thus have broad application prospects and enormous market potential. In PCBs, the surface roughness of the copper foil is a significant factor affecting signal transmission loss, especially in signal transmission frequencies exceeding 50 GHz. High-frequency signals inevitably experience a skin effect on rough conductor surfaces during transmission. When signals are transmitted only within the rough layer, severe standing waves and reflections inevitably occur, resulting in significant signal loss or even complete distortion. Therefore, researching and developing the production technology and industrializing fourth-generation high-precision ultra-low profile electronic copper foil (HVLP) can provide crucial support for the development of China's electronic information industry.

[0004] Fourth-generation HVLP electronic copper foil features lower surface roughness (roughness Rz ≤ 0.7μm), resulting in a smoother surface profile. This significantly reduces signal attenuation and distortion during high-frequency signal transmission at high speeds, while also exhibiting excellent circuit etching properties and high-speed signal transmission capabilities. It represents the latest technical requirement for high-frequency, high-speed printed circuit boards and is widely used in industries such as 5G / 6G communications, high-end servers, and AI chips. Therefore, fourth-generation HVLP copper foil requires both extremely low surface roughness to ensure high-frequency signal transmission performance and enhanced adhesion between the copper foil and the resin substrate to guarantee product stability. Finding a balance between low roughness and high peel strength is a pressing technical challenge. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide an HVLP4 electronic copper foil and its preparation method.

[0006] The specific technical solution of the present invention is as follows: In a first aspect, the present invention provides an HVLP4 electronic copper foil, the electronic copper foil comprising a copper foil substrate and a gradient nano-nodular layer, a multi-element alloy layer, an anti-oxidation layer and a composite coupling agent layer sequentially formed on the rough surface of the copper foil substrate; The gradient nano-nodular layer consists of a dense nodular layer with a particle size of 50-250 nm and a surface nodular layer with a particle size of 250-450 nm, arranged sequentially from the copper foil substrate outwards.

[0007] Secondly, the present invention provides a method for preparing HVLP4 electronic copper foil as described above, comprising the following steps: S1. Provide electrolytic copper foil raw material; S2, Gradient nodularization process: A nano-nodularization layer with a gradient particle size distribution is formed on the surface of the original foil by stepwise electrodeposition; S3, Multi-element alloy layer treatment process: Electroplating is performed on the surface of the nano-nodular layer to form a multi-element alloy layer; S4. Anti-oxidation treatment process: An anti-oxidation layer is formed by electroplating on the surface of the multi-element alloy layer; S5. Composite Coupling Agent Coating Process: A water-based composite coupling agent is coated on the surface of the anti-oxidation layer, and after drying, the HVLP4 electronic copper foil product is obtained.

[0008] Further, step S2 includes: The electrolytic foil is passed sequentially through the first roughening tank and the second roughening tank; The process conditions of the first roughening tank are: current density 10.0-20.0 A / dm², electroplating time 10-25 s, and the roughening solution contains 100.0-180.0 g / L sulfuric acid, 5.0-30.0 g / L divalent copper ions, 10-40 ppm chloride ions, and 200-800 ppm polyvinylpyrrolidone, 100-300 ppm ethylenediamine, and 80-400 ppm sodium thiazoline dithiopropanesulfonate. The process conditions for the second roughening tank are as follows: current density 5.0-10.0 A / dm², electroplating time 10-25 s, and the roughening solution contains 100.0-180.0 g / L sulfuric acid, 5.0-20.0 g / L divalent copper ions, 10-40 ppm chloride ions, 100-500 ppm gelatin-acrylamide graft copolymer, 50-100 ppm sodium 2,3-dimercaptosulfonate, and 50-150 ppm sodium borate.

[0009] Further, the process conditions for step S3 are as follows: temperature 30-45℃, current density 0.1-1.0A / dm², the electroplating solution containing 1.0-5.0g / L nickel sulfate or nickel chloride, 2.0-5.0g / L zinc sulfate, 0.1-1.0g / L sodium dodecyl sulfate, 5.0-20.0g / L tetrakis(2-hydroxypropyl)ethylenediamine, pH value 9.0-11.0, and the electroplating solution also contains metal ions with a concentration of 50-300ppm, wherein the metal ions are selected from at least one of transition metal ions and rare earth metal ions.

[0010] Furthermore, the metal ion is selected from at least one of cobalt ions, lanthanum ions, and cerium ions.

[0011] Furthermore, the metal ions are sourced from cobalt sulfate, lanthanum chloride, or cerium sulfate.

[0012] Further, the process conditions for step S4 are: temperature 30-45℃, current density 3.0-10.0A / dm², electrolyte containing 0.5-1.5g / L hexavalent chromium ions, and pH value 10.0-12.0.

[0013] Further, in step S5, the concentration of the aqueous composite coupling agent is 0.1-2.0 wt%, and the aqueous composite coupling agent comprises a phosphate coupling agent and a silane coupling agent.

[0014] Furthermore, the phosphate coupling agent is selected from one of epoxy phosphate and 2-hydroxyethyl methacrylate phosphate; the silane coupling agent is selected from one or two of KH550, KH560, KH570, and KH590.

[0015] Furthermore, in the aqueous composite coupling agent, the mass ratio of the phosphate ester coupling agent to the silane coupling agent is (0.5-2.0):1.

[0016] Furthermore, the mass ratio of the phosphate coupling agent to the silane coupling agent is 1:1.

[0017] Furthermore, the surface roughness Rz of the electronic copper foil is ≤0.7μm, and the normal peel strength of the electronic copper foil after lamination to the PPO substrate is ≥0.45N / mm.

[0018] Thirdly, the present invention provides the application of the above-mentioned HVLP4 electronic copper foil or the HVLP4 electronic copper foil prepared by the above-mentioned preparation method in the preparation of printed circuit boards.

[0019] Compared with the prior art, the beneficial technical effects of this invention are reflected in: 1. Achieving an excellent balance between ultra-low roughness and high peel strength: This invention, through gradient nano-nodular structure design, preparation of multi-element alloy layers and surface treatment process of coating composite coupling agent, significantly improves the peel strength between copper foil and different resin substrates (such as PPO substrate) while maintaining an ultra-low roughness of Rz≤0.7μm, thus solving the technical problem of difficulty in achieving both low roughness and high peel strength in the prior art.

[0020] 2. The gradient nodule layer provides physical anchoring and enhances interfacial bonding: In this invention, the gradient nano-nodular layer design first uses a first roughening groove to electrodeposit a dense nodular layer with small particle size on a copper foil substrate as the bottom layer. Then, a second roughening groove is used to continue electrodepositing on this bottom layer to grow a surface nodular layer with larger particle size. This bilayer structure, with particle size gradually increasing from the inside out, constitutes the gradient morphology. The dense bottom layer ensures a strong bond between the nodular particles and the substrate, while the larger particle size of the surface layer further increases the specific surface area. This gradient design achieves precise control over the nodular growth process, effectively avoiding the problem of increased surface roughness due to excessively large single nodular particle size. While maintaining an overall ultra-low roughness, it maximizes the physical anchoring force with the resin substrate.

[0021] 3. The multi-alloy heat-resistant layer plays a role in blocking heat diffusion and improving high-temperature stability: The multi-alloy heat-resistant layer set in this invention acts as a barrier layer, which can effectively fix the nodular layer structure and prevent the bottom copper substrate from diffusing outward under high temperature environment, thereby giving the copper foil excellent heat resistance and high-temperature stability.

[0022] 4. The anti-oxidation layer provides anti-oxidation protection and maintains surface stability: This invention forms a dense protective film on the copper foil surface to isolate it from air by preparing an anti-oxidation layer. This anti-oxidation protective film works together with the multi-alloy heat-resistant layer to effectively protect the various properties of the copper foil and maintain the long-term stability of the copper foil surface.

[0023] 5. The composite coupling agent layer provides a chemical bonding mechanism, resulting in a synergistic effect: This invention introduces a composite coupling agent system, which utilizes its chemical bonding effect to form a strong synergistic effect with the physical anchoring structure provided by the underlying gradient nodule layer, thereby enhancing the interfacial bonding strength between the copper foil and the resin.

[0024] 6. Excellent comprehensive physicochemical properties: Through the synergistic mechanism among the various layers mentioned above, the electronic copper foil produced by this invention exhibits superior performance in all aspects. Its surface roughness is extremely low, significantly reducing high-frequency signal attenuation and distortion; simultaneously, it demonstrates excellent peel strength and superior oxidation resistance, exhibiting no oxidation or discoloration after baking at 200℃ for 40 minutes. This meets the stringent requirements of high-frequency, high-speed copper foil in industries such as 5G / 6G communications, high-end servers, and AI chip intelligence.

[0025] By combining the synergistic effects of the above processes, the finished foil produced by this invention can meet the following technical standards: Attached Figure Description

[0026] Figure 1 This is a SEM microstructure image of the copper foil prepared in Example 1 of the present invention. Detailed Implementation

[0027] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0028] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0029] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that excludes other embodiments. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0030] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0031] Example 1 The first embodiment of the present invention provides a smooth profile HVLP4 electronic copper foil for high-frequency and high-speed copper-clad laminates and a method for preparing the same. The steps include an electrolytic foil process, a gradient nodule treatment process, a multi-element alloy layer treatment process, an anti-oxidation treatment process, and a composite coupling agent coating process. The specific steps are as follows: The gradient nodulation process is as follows: the original foil (thickness 35μm, smooth surface Ra 0.31μm, rough surface Rz=0.59μm) generated by the electrolytic original foil process is passed sequentially through two roughening tanks: First roughening tank (dense nodular layer): Electrolyte composition: Cu 2+ Concentration 18.0 g / L, H2SO4 concentration 140.0 g / L, chloride ion concentration 30 ppm, ethylenediamine addition 200 ppm, polyvinylpyrrolidone addition 500 ppm, sodium thiazoline dithiopropanesulfonate addition 200 ppm; current density 20.0 A / dm², electroplating time 20 seconds.

[0032] Second roughening tank (surface roughening layer): Electrolyte composition: Cu 2+ Concentration 10.0 g / L, H2SO4 concentration 100.0 g / L, chloride ion concentration 30 ppm, gelatin-acrylamide graft copolymer (model R-JZ-0009, Xi'an Ruixi Biotechnology Co., Ltd.) addition amount 400 ppm, sodium 2,3-dimercaptosulfonate addition amount 80 ppm, sodium borate addition amount 120 ppm; current density 8.0 A / dm², electroplating time 20 seconds.

[0033] Testing revealed that the dense nodular layer formed by the first coarsening groove had a particle size of 50-200 nm, while the surface nodular layer formed by the second coarsening groove had a particle size of 250-400 nm.

[0034] In this embodiment, the geometric spatial constraint effect of the copper tooth microstructure on the copper foil surface is utilized during the gradient nodulation process to achieve precise spatial deposition of nodulation particles: in the gaps between the copper teeth, due to spatial limitations, only the first-stage small-diameter nodulation particles can be deposited, forming a single-layer dense nodulation; while at the tips and open areas of the copper teeth, the space is larger, allowing the sequential deposition of a small-diameter dense nodulation layer and a large-diameter surface coarse nodulation layer, forming a double-layer gradient nodulation structure. This spatially constrained hierarchical deposition method achieves maximum coating and anchoring of the copper tooth microstructure by nanoparticles while maintaining a rough surface Rz ≤ 0.7 μm.

[0035] The multi-element alloy layer processing step is as follows: the original foil after the gradient nodulation treatment is subjected to an electrolyte of 2.5 g / L nickel sulfate, 4.0 g / L zinc sulfate, 0.5 g / L sodium dodecyl sulfate, and 15.0 g / L tetrakis(2-hydroxypropyl)ethylenediamine at a temperature of 40°C and a current density of 0.5 A / dm³. 2 Electroplating was performed at a pH of 10.0, with the additives containing 200 ppm of lanthanum chloride and cerium sulfate (lanthanum ion to cerium ion molar ratio 1:1).

[0036] The anti-oxidation treatment process involves electroplating the original foil, which has undergone the multi-element alloy layer treatment process, at a temperature of 40°C, with 1.2 g / L of hexavalent chromium ions (the compound source providing hexavalent chromium ions is potassium chromate), a pH value of 11.0, and a current density of 5.0 A / dm2 for 20 seconds to form a passivation layer.

[0037] The composite coupling agent coating process is as follows: the original foil, after undergoing an anti-oxidation treatment, is coated with a 0.8 wt% aqueous composite coupling agent. This aqueous composite coupling agent is prepared by mixing 95 wt% epoxy phosphate ester CM-801 (Guangdong Jiaming Chemical Co., Ltd.) and KH570 silane coupling agent at a mass ratio of 1:1. After the coupling agent coating process, the foil is dried for 10 seconds at 120 degrees Celsius, then wound up to obtain the finished HVLP4 electronic copper foil.

[0038] The concentration of the aqueous composite coupling agent refers to the percentage of the total mass of the coupling agent to the total mass of the aqueous composite coupling agent. For example, when epoxy phosphate and KH570 silane coupling agent are used as composite coupling agents, and the concentration of both coupling agents in their stock solutions is 95wt%, to prepare an aqueous composite coupling agent with a target concentration of 0.8wt%, take 1g of epoxy phosphate stock solution and 1g of KH570 stock solution. The total mass of the active ingredient in the coupling agent is then 1g×95%+1g×95%=1.9g. Add deionized water to a total mass of 237.5g (i.e., add 235.5g of deionized water), and stir evenly to obtain an aqueous composite coupling agent with a concentration of 0.8wt%. The concentration of the aqueous composite coupling agent described in this invention is calculated in this manner.

[0039] The 35μm HVLP4 electronic copper foil prepared in this example was tested using the IPC-TM-650 method. The surface roughness Ra was 0.33μm, the surface roughness Rz was 0.66μm, the peel strength after lamination was 0.61 N / mm under normal conditions, and the peel strength after tin immersion was 0.50 N / mm. It did not discolor after baking at 200℃ for 40 min. All performance indicators are qualified.

[0040] Figure 1 The image shows a SEM image of the copper foil prepared in this embodiment. As can be seen from the image, the particle size is very small, the surface profile is smooth and the roughness is small, which meets the requirement that the surface roughness Rz ≤ 0.7 μm.

[0041] Example 2 The second embodiment of the present invention provides a smooth profile HVLP4 electronic copper foil for high-frequency and high-speed copper-clad laminates and a method for preparing the same. The steps include an electrolytic foil process, a gradient nodule treatment process, a multi-element alloy layer treatment process, an anti-oxidation treatment process, and a composite coupling agent coating process. The specific steps are as follows: In the electrolytic foil process, an electrolytic foil with a thickness of 18 μm, a smooth surface Ra=0.31, and a rough surface Rz=0.60 is selected. The gradient nodulation treatment process involves passing the foil sequentially through two roughening tanks: First roughening tank (dense nodular layer): Electrolyte composition: Cu 2+ Concentration 25.0 g / L, H2SO4 concentration 160.0 g / L, chloride ion concentration 45 ppm, ethylenediamine addition 300 ppm, polyvinylpyrrolidone addition 600 ppm, sodium thiazoline dithiopropanesulfonate addition 300 ppm; current density 25.0 A / dm², electroplating time 25 seconds.

[0042] Second roughening tank (surface roughening layer): Electrolyte composition: Cu 2+ The concentration was 15.0 g / L, H2SO4 concentration was 120.0 g / L, chloride ion concentration was 45 ppm, gelatin-acrylamide graft copolymer (model R-JZ-0009) addition amount was 500 ppm, sodium 2,3-dimercaptosulfonate addition amount was 100 ppm, sodium borate addition amount was 150 ppm; current density was 12.0 A / dm², electroplating time was 25 seconds.

[0043] Testing revealed that the dense nodular layer formed by the first coarsening groove had a particle size of 80-250 nm, while the surface nodular layer formed by the second coarsening groove had a particle size of 250-450 nm.

[0044] The multi-element alloy layer treatment process is as follows: the original foil after the gradient nodulation treatment is electroplated at a temperature of 45°C, with an electrolyte of 3.5 g / L nickel sulfate, 5.0 g / L zinc sulfate, 0.8 g / L sodium dodecyl sulfate, and 20.0 g / L tetra(2-hydroxypropyl)ethylenediamine, a current density of 0.8 A / dm², and a pH of 11.0. The additives include 300 ppm of lanthanum chloride and cerium sulfate (lanthanum ion to cerium ion molar ratio 1:1). The anti-oxidation treatment process involves electroplating the original foil after the multi-element alloy layer treatment at a temperature of 45°C, with 1.5 g / L hexavalent chromium ions (provided by potassium chromate), a pH of 11.5, and a current density of 6.0 A / dm² for 25 seconds to form a passivation layer.

[0045] The composite coupling agent coating process is as follows: The original foil, after undergoing an anti-oxidation treatment, is coated with a 1.2 wt% aqueous composite coupling agent. This aqueous composite coupling agent is prepared by mixing 2-hydroxyethyl methacrylate phosphate (brand name KM2110, Hangzhou Furui Technology Co., Ltd., concentration 95 wt%) and KH550 silane coupling agent (concentration 95 wt%) in a 1:1 mass ratio. After the coupling agent coating process, the foil is dried at 120℃ for 30 seconds and then wound up to obtain a 35 μm HVLP4 electronic copper foil product.

[0046] The 18μm copper foil prepared in this example was tested using the IPC-TM-650 method. The surface roughness Rz was 0.65, the smooth surface roughness Ra was 0.32, the normal peel strength after lamination was 0.48 N / mm, the thermal shock peel strength after immersion in tin at 288℃ for 5 min was 0.49 N / mm, and it did not discolor after baking at 200℃ for 40 min. All performance indicators are qualified.

[0047] Comparative Example 1 The method for preparing the smooth contour electronic copper foil in this example includes the following steps: The conventional HVLP copper foil preparation process was adopted: using HVLP copper foil with the same low roughness as in Example 1 (original foil thickness 35 μm, smooth surface Ra 0.31 μm, rough surface Rz = 0.59 μm), only one nodulation treatment was performed to obtain a single nodulation layer without gradient structure. The roughening solution adopted the formulation and process of the second roughening tank in Example 1; the alloy heat-resistant layer was a Ni-Zn alloy layer (without rare earth addition); and 0.8 wt% of 2-hydroxyethyl methacrylate phosphate coupling agent was used. Other conditions remained consistent with Example 1.

[0048] The HVLP4 electronic copper foil prepared in this example was tested using the IPC-TM-650 method. The smooth surface Ra=0.43, the rough surface Rz=0.87μm, the peel strength after lamination under normal conditions was 0.38N / mm, the tin-immersion peel strength was 0.35N / mm, and it did not change color after baking at 200℃ for 40 minutes. The performance indicators are unqualified.

[0049] Comparative Example 2 (Single Tumor Treatment) This embodiment is basically the same as Embodiment 1, except that the gradient nodule formation process is not performed; only a single roughening tank is used for a single nodule formation process. The specific steps are as follows: The single nodulation treatment process is as follows: the original foil (thickness 35μm, smooth surface Ra=0.31μm, rough surface Rz=0.59μm) generated by the electrolytic original foil process is passed through only one roughening tank. This roughening tank adopts the formulation and process of the first roughening tank in Example 1, specifically: the electrolyte composition includes Cu2+ The concentrations were 18.0 g / L, H2SO4 140.0 g / L, chloride ion 30 ppm, ethylenediamine 200 ppm, polyvinylpyrrolidone 500 ppm, and sodium thiazoline dithiopropanesulfonate 200 ppm; the current density was 20.0 A / dm², and the electroplating time was 20 seconds.

[0050] The process parameters and additive components (including rare earth metal ions such as lanthanum chloride and cerium sulfate contained in the multi-element alloy layer, as well as the water-based composite coupling agent) of the multi-element alloy layer treatment process, anti-oxidation treatment process, and composite coupling agent coating process are exactly the same as those in Example 1.

[0051] The 35μm HVLP4 electronic copper foil prepared in this example was tested using the IPC-TM-650 method. The surface roughness was Ra=0.37 for smooth surfaces and Rz=0.82 for rough surfaces. The peel strength after lamination was 0.43 N / mm, and the tin-immersion peel strength was 0.38 N / mm. It did not discolor after baking at 200℃ for 40 min. However, both the peel strength after lamination and the tin-immersion peel strength were unqualified.

[0052] Comparative Example 3 (using a single silane) This embodiment is basically the same as Embodiment 1, except that a single silane coupling agent is used in the coating coupling agent process. The specific steps are as follows: The process parameters and electrolyte composition of the gradient nodule treatment process, the multi-element alloy layer treatment process, and the anti-oxidation treatment process are exactly the same as those in Example 1.

[0053] The composite coupling agent coating process is replaced by a single coupling agent coating process: the original foil, after the anti-oxidation treatment process, is coated with a 0.8 wt% aqueous coupling agent, which is only a KH560 silane coupling agent solution. After the coupling agent coating process, the foil is dried and wound up to obtain the finished electronic copper foil.

[0054] The HVLP4 electronic copper foil prepared in this example was tested using the IPC-TM-650 method. The smooth surface roughness Ra = 0.33 μm, the rough surface roughness Rz = 0.65 μm, the peel strength after lamination was 0.25 N / mm, and the tin-immersion peel strength was 0.23 N / mm. It did not discolor after baking at 200℃ for 40 min. However, its normal peel strength and tin-immersion peel strength are both unqualified.

[0055] A comparison of the data from Example 1 and Comparative Examples 1-3 shows that Example 1 of this invention, by employing a gradient nodulation process (compared to the single nodulation in Comparative Example 2), effectively increases the specific surface area of ​​the treated surface, providing a strong physical anchoring effect. Simultaneously, the application of a composite coupling agent system (compared to the single coupling agent in Comparative Example 3) produces an excellent synergistic effect of chemical bonding. Combined with the protective mechanisms of the multi-element alloy heat-resistant layer and the anti-oxidation layer, this invention, through the synergistic effect of the above-mentioned technical means, successfully achieves an excellent balance between ultra-low roughness and high peel strength (significantly improved compared to the conventional process of Comparative Example 1). The resulting HVLP4 electronic copper foil can meet the stringent requirements of high-frequency, high-speed copper foil in high-end application scenarios such as 5G / 6G communication and AI servers.

[0056] The above detailed description is a specific description of one of the feasible embodiments of the present invention. This embodiment is not intended to limit the patent scope of the present invention. All equivalent implementations or modifications that do not depart from the present invention should be included within the scope of the technical solution of the present invention.

[0057] It should be particularly noted that the various embodiments listed in this specification and accompanying drawings are intended to illustrate the technical solutions and advantages of the present invention, and not to limit the scope of protection of the present invention. Without departing from the core ideas and technical effects of the present invention, those skilled in the art can make any form of improvement, substitution, combination, or modification to the structural arrangement, process parameters, material selection, control logic, etc., of the described embodiments; any obvious changes based on the same concept should be considered equivalent solutions of the present invention and should be included within the scope of protection defined by the claims of the present invention. The actual scope of protection of the present invention is determined by the appended claims and should be correctly understood in conjunction with the specification and accompanying drawings.

Claims

1. An HVLP4 electronic copper foil, characterized in that, The electronic copper foil includes a copper foil substrate and a gradient nano-nodular layer, a multi-element alloy layer, an anti-oxidation layer and a composite coupling agent layer sequentially formed on the rough surface of the copper foil substrate. The gradient nano-nodular layer consists of a dense nodular layer with a particle size of 50-250 nm and a surface nodular layer with a particle size of 250-450 nm, arranged sequentially from the copper foil substrate outwards.

2. A method for preparing HVLP4 electronic copper foil as described in claim 1, characterized in that, Includes the following steps: S1. Provide electrolytic copper foil raw material; S2, Gradient nodularization process: A nano-nodularization layer with a gradient particle size distribution is formed on the surface of the original foil by stepwise electrodeposition; S3, Multi-element alloy layer treatment process: Electroplating is performed on the surface of the nano-nodular layer to form a multi-element alloy layer; S4. Anti-oxidation treatment process: An anti-oxidation layer is formed by electroplating on the surface of the multi-element alloy layer; S5. Composite Coupling Agent Coating Process: A water-based composite coupling agent is coated on the surface of the anti-oxidation layer, and after drying, the HVLP4 electronic copper foil product is obtained.

3. The preparation method according to claim 2, characterized in that, Step S2 includes: The original electrolytic copper foil is passed sequentially through the first roughening tank and the second roughening tank; The process conditions of the first roughening tank are: current density 10.0-20.0 A / dm², electroplating time 10-25 s, and the roughening solution contains 100.0-180.0 g / L sulfuric acid, 5.0-30.0 g / L divalent copper ions, 10-40 ppm chloride ions, and 200-800 ppm polyvinylpyrrolidone, 100-300 ppm ethylenediamine, and 80-400 ppm sodium thiazoline dithiopropanesulfonate. The process conditions for the second roughening tank are as follows: current density 5.0-10.0 A / dm², electroplating time 10-25 s, and the roughening solution contains 100.0-180.0 g / L sulfuric acid, 5.0-20.0 g / L divalent copper ions, 10-40 ppm chloride ions, 100-500 ppm gelatin-acrylamide graft copolymer, 50-100 ppm sodium 2,3-dimercaptosulfonate, and 50-150 ppm sodium borate.

4. The preparation method according to claim 2, characterized in that, The process conditions for step S3 are as follows: temperature 30-45℃, current density 0.1-1.0A / dm², the electroplating solution containing 1.0-5.0g / L nickel sulfate or nickel chloride, 2.0-5.0g / L zinc sulfate, 0.1-1.0g / L sodium dodecyl sulfate, 5.0-20.0g / L tetra(2-hydroxypropyl)ethylenediamine, pH value 9.0-11.0, and the electroplating solution also contains metal ions with a concentration of 50-300ppm, wherein the metal ions are selected from at least one of transition metal ions and rare earth metal ions.

5. The preparation method according to claim 4, characterized in that, The metal ion is selected from at least one of cobalt ion, lanthanum ion and cerium ion.

6. The preparation method according to claim 2, characterized in that, The process conditions for step S4 are: temperature 30-45℃, current density 3.0-10.0A / dm², electrolyte containing 0.5-1.5g / L hexavalent chromium ions, and pH value 10.0-12.

0.

7. The preparation method according to claim 2, characterized in that, In step S5, the concentration of the aqueous composite coupling agent is 0.1-2.0 wt%, and the composite coupling agent comprises a phosphate coupling agent and a silane coupling agent.

8. The preparation method according to claim 7, characterized in that, The phosphate coupling agent is selected from one of epoxy phosphate and 2-hydroxyethyl methacrylate phosphate; the silane coupling agent is selected from one or two of KH550, KH560, KH570, and KH590.

9. The HVLP4 electronic copper foil according to claim 1, characterized in that, The surface roughness Rz of the electronic copper foil is ≤0.7μm, and the normal peel strength of the electronic copper foil after lamination to the PPO substrate is ≥0.45N / mm.

10. The application of the HVLP4 electronic copper foil according to claim 1 or the HVLP4 electronic copper foil prepared by the preparation method according to any one of claims 2-8 in the preparation of printed circuit boards.

Images