Carrier-attached copper foil and method for manufacturing the same

Abstract

This invention belongs to the field of printed circuit board manufacturing, specifically relating to a carrier copper foil and its preparation method. The carrier copper foil includes a metal carrier layer, on the surface of which a conductive polymer release layer is grown in situ. The conductive polymer release layer comprises a conductive polymer, nano-photocatalyst particles doped with the conductive polymer, and aromatic sulfonate compounds. The nano-photocatalyst particles are formed by photocatalytic monomer polymerization of the conductive polymer. The aromatic sulfonate compounds enhance the heat resistance of the conductive polymer to prevent carbonization of the release layer at PCB lamination temperatures. An ultrathin copper layer is electrodeposited on the conductive polymer release layer. This invention utilizes photocatalysis technology to achieve in-situ growth of the conductive polymer, which is beneficial for the uniform electrodeposition of the ultrathin copper layer. The presence of aromatic sulfonate compounds doped in the conductive polymer film utilizes their steric hindrance effect and π-π stacking effect to solve the problem of "thermal lock-up" in organic intermediate release layers.

Description

Technical Field

[0001] This invention belongs to the field of printed circuit board manufacturing, specifically relating to a carrier copper foil and its preparation method. Background Technology

[0002] As electronic devices become thinner, lighter, and more powerful, the requirements for circuit precision in printed circuit boards (PCBs) and IC substrates are becoming increasingly stringent. Manufacturing high-density interconnect circuit boards with line widths / spacings of less than 30 / 30μm based on the semi-additive process (mSAP) has become one of the most important mainstream processes.

[0003] The semi-additive process (mSAP) requires first bonding an ultrathin copper layer to a substrate, then forming intricate circuitry through methods such as pattern electroplating for thickening and etching of the base copper. Ultrathin copper foil (≤5μm thickness) combined with carrier-attached copper foil (CACF) is a crucial method for forming ultrathin copper layers, directly impacting the manufacturing efficiency and circuit quality of this type of PCB. The core of CACF lies in the intermediate release layer, which must possess suitable peel strength, excellent high-temperature resistance, and good conductivity.

[0004] Common materials for intermediate release layers are divided into metallic and organic types. Metallic release layer materials include elements such as Ni, Mo, Co, Cr, Fe, Ti, W, and Zn, or their alloys, and can be fabricated using methods such as electroplating, electroless plating, magnetron sputtering, and physical vapor deposition. Although metallic release layers are heat-resistant, they are prone to pinholes, which can cause "spot welds" that cannot be removed, and subsequent etching to remove residues is also quite difficult.

[0005] Organic intermediate release layers often utilize small molecules such as silanes, carboxylic acids, and imidazoles, and can be prepared through methods such as impregnation, spraying, and coating. These organic materials are mostly insulating substances, relying on the tunneling effect generated by extremely thin thicknesses (<5nm) for conductivity. This can lead to problems such as localized areas where electroplating is impossible when electroplating ultrathin copper layers. Improving the conductivity of organic intermediate release layers is one of the effective means to enhance electroplating uniformity.

[0006] Conductive polymers (such as polypyrrole and polyaniline) are theoretically ideal release layer materials due to their intrinsic conductivity and the flexibility of their polymer backbone. There are two main pathways for preparing conductive polymer release layers: electrochemical polymerization and physical coating. However, the following problems exist when fabricating intermediate release layers: 1. Electrochemical polymerization: An anodic voltage needs to be applied to the copper substrate. Due to the low oxidation potential of copper, the copper substrate is prone to anodic dissolution (corrosion) under the polymerization voltage, which leads to the destruction of the interfacial structure and makes it difficult to form a continuous and dense film.

[0007] 2. Physical coating: A pre-prepared conductive polymer slurry is applied to the surface of the copper foil. This method suffers from weak interfacial adhesion, easy flow marks, and difficulty in controlling the coating thickness to the nanometer level (it is usually quite thick), making it difficult to meet the low profile requirements of ultra-thin copper foil.

[0008] In addition, existing organic release layers often experience a sharp increase in peel force ("thermal lock-up" effect) due to thermal decomposition or diffusion reaction with copper in the high-temperature (>200℃) environment of PCB lamination, which seriously affects product yield.

[0009] Our research group's Chinese invention patent application CN120330819A, published on July 18, 2025, proposes a method using thiol-functionalized ionic liquids such as 1-(2-mercaptoethyl)-3-methylimidazole bromide and 1-(4-mercaptobutyl)-3-methylimidazole bromide as the intermediate release layer for the copper foil substrate. The release strength can be controlled by adjusting the treatment time in the ionic liquid. However, this method has certain limitations for industrial implementation: firstly, the production cost of thiol-functionalized ionic liquids such as 1-(2-mercaptoethyl)-3-methylimidazole bromide is relatively high; secondly, the required immersion time in the ionic liquid is long, at least 4 hours, and typically 4-25 hours, which significantly challenges the industrial production efficiency of the substrate copper foil.

[0010] Overall, existing organic carrier copper foils suitable for industrial production still suffer from problems such as uneven electroplating of ultra-thin copper layers and high-temperature peeling lock-up at PCB lamination temperatures. Summary of the Invention

[0011] The purpose of this invention is to provide a carrier copper foil that solves the problems of uneven electroplating of ultra-thin copper layers and high-temperature peeling lock-up at PCB lamination temperatures in existing organic carrier copper foils.

[0012] The second objective of this invention is to provide a method for preparing a carrier copper foil, which solves the problems of easy flow marks and difficulty in controlling the coating thickness to the nanometer level (usually quite thick) when conductive polymer paste is coated on the surface of copper foil.

[0013] To achieve the above objectives, the technical solution of the copper foil carrier of the present invention is as follows: A copper foil with a carrier includes a metal carrier layer, on the surface of which a conductive polymer release layer is grown in situ. The conductive polymer release layer includes a conductive polymer, nano-photocatalyst particles doped in the conductive polymer, and an aromatic sulfonate compound. The nano-photocatalyst particles are formed by photocatalytic monomer polymerization to form the conductive polymer. The aromatic sulfonate compound enhances the heat resistance of the conductive polymer to prevent the release layer from carbonizing at PCB lamination temperatures. An ultrathin copper layer is electrodeposited on the conductive polymer release layer.

[0014] This invention is an improved invention that uses photocatalytic technology to achieve "potential-free" in-situ growth of conductive polymers on the copper surface. The thickness of the conductive polymer film is controlled at the nanometer level and the surface is dense, which is conducive to the uniform electrodeposition of the ultrathin copper layer. The conductive polymer film is doped with aromatic sulfonate compounds, which can utilize their steric hindrance effect and π-π stacking effect to significantly improve the thermal stability of the conductive polymer. This avoids the inability to peel off or damage to the ultrathin copper layer during peeling due to the sharp increase in peeling force at PCB lamination temperature, and solves the problem of "thermal deadlock" in the intermediate peeling layer of organic materials.

[0015] Preferably, the thickness of the conductive polymer exfoliating layer is 30-150 nm, and the particle size of the nano-photocatalyst particles is 10-50 nm; the nano-photocatalyst particles are nano-titanium dioxide, nano-zinc oxide, or graphitic carbon nitride. Controlling the particle size of the nano-photocatalyst within the above range results in a uniform and dense intermediate exfoliating layer with good conductivity, leading to a dense and bright ultrathin copper layer with high surface quality.

[0016] Preferably, the aromatic sulfonate compound is sodium 1,5-naphthalenedisulfonate, sodium anthraquinone sulfonate, or sodium polystyrene sulfonate. These aromatic sulfonate compounds are low in cost and can achieve good high-temperature resistance with relatively small doping amounts.

[0017] Preferably, the total thickness of the carrier copper foil is 15~75μm, wherein the thickness of the metal carrier layer is 12~70μm and the thickness of the ultrathin copper layer is 1.5~5μm; the normal peel strength of the carrier copper foil is 0.2~0.4N / cm, and the peel strength change rate after 1 hour of heat aging at 260℃ is <20%, or <10%. Controlling the carrier layer and ultrathin copper layer of the carrier copper foil within the above-mentioned thickness range can keep the normal peel strength and the peel strength after 260℃ / 1h heat aging within the ideal range, which is beneficial to improving the yield of PCB products.

[0018] Preferably, the monomer is pyrrole, 3,4-ethylenedioxythiophene, or aniline. The formation of polypyrrole, poly3,4-ethylenedioxythiophene, and polyaniline structures through photocatalytic polymerization of these monomers exhibits better intrinsic conductivity and skeletal flexibility, making them more ideal materials as intermediate release layers.

[0019] The technical solution of the method for preparing the carrier copper foil of the present invention is as follows: A method for preparing a copper foil carrier includes the following steps: preparing a photosensitive precursor solution with conductive polymer monomers, nano-photocatalysts, aromatic sulfonate compounds and solvents; coating the photosensitive precursor solution onto a pretreated metal foil carrier to form a liquid film; then performing photocatalytic in-situ polymerization to form a conductive polymer release layer; and finally electroplating an ultrathin copper layer on the conductive polymer release layer.

[0020] The method for preparing carrier copper foil provided by this invention employs photocatalytic in-situ growth of a conductive polymer release layer, which requires no voltage application, does not corrode the copper substrate, and enables precise nanoscale thickness control. The in-situ incorporation of aromatic sulfonate compounds into the conductive polymer film effectively enhances the high-temperature stability of the intermediate release layer. Furthermore, this method eliminates the need for expensive equipment such as vacuum sputtering, and features a fast photo-irradiation reaction speed (on the order of seconds), making it suitable for continuous roll-to-roll production.

[0021] Preferably, in the photosensitive precursor solution, the concentration of the conductive polymer monomer is 0.1~0.5 mol / L, the added mass of the nano-photocatalyst is 0.5~3.0% of the monomer mass; the concentration of the aromatic sulfonate compound is 0.05~0.2 mol / L; and the pH is 3.0~6.0. Controlling the conductive polymer monomer, nano-photocatalyst, and aromatic sulfonate compound in the photosensitive precursor solution at the above concentrations allows for the rapid formation of a thin film with good adsorption, preparing for the subsequent photocatalytic process.

[0022] More preferably, the coating is performed using a dip-coating method or a coating method, wherein the dip-coating speed is 3~5 mm / s. The liquid film produced by the dip-coating method exhibits good uniformity, which is beneficial for forming a high-quality conductive polymer layer.

[0023] Preferably, during the photocatalytic in-situ polymerization, ultraviolet or blue light source irradiation is used, with a light intensity of 20~100 mW / cm². 2 The irradiation time is 30~120s. The conductive polymer release layer formed under the above photocatalytic parameters ensures the density (no pinholes) of subsequent electroplating and achieves precise control of the release force.

[0024] Preferably, the current density for electroplating to form the ultrathin copper layer is 5~50 A / dm². 2 The electroplating time is 1-3 minutes, and the thickness of the ultrathin copper layer is 1.5-5 μm. Using the above electroplating parameters, the ultrathin copper layer prepared exhibits good surface density, which well meets the requirements of subsequent PCB manufacturing.

[0025] Compared with the prior art, the present invention has the following outstanding features and advantages: 1. No potential corrosion, intact interface: Photocatalytic polymerization is used, which eliminates the need to apply voltage to the copper foil, fundamentally solving the technical pain point of copper substrate dissolution in electrochemical polymerization and ensuring the integrity of the microstructure of the carrier copper foil surface.

[0026] 2. Excellent high temperature resistance: The introduction of macromolecular aromatic sulfonates (such as sodium naphthalene disulfonate) as dopants, utilizing their steric hindrance effect and π-π stacking effect, significantly improves the thermal stability of conductive polymers. After thermal aging at 260℃ / 1h, the peel force change rate is <20%, solving the problem of "thermal deadlock".

[0027] 3. Simple process and low cost: It eliminates the need for vacuum sputtering equipment and has a fast light-induced reaction speed (seconds), making it suitable for roll-to-roll continuous production. Attached Figure Description

[0028] Figure 1 This is a sample image of the method for preparing the carrier copper foil in Embodiment 1 of the present invention; Figure 2 This is a SEM image of the polypyrrole release layer in Example 1 of the present invention; Figure 3 The above are the EDS characterization results of the polypyrrole release layer in Example 1 of this invention; Figure 4 The results are FTIR characterizations of the polypyrrole release layer in Example 1 of this invention. Figure 5 This is a SEM image of the ultrathin copper foil in Embodiment 1 of the present invention. Detailed Implementation

[0029] (I) Preferred embodiments of the copper foil with carrier and the preparation method thereof of the present invention The design concept of the copper foil carrier of the present invention is to use photocatalytic technology to achieve "potential-free" in-situ growth of conductive polymers on the copper surface, avoiding copper corrosion that is prone to occur during electrochemical polymerization; and to improve the high-temperature stability of the intermediate release layer by introducing heat-resistant dopants.

[0030] The aforementioned carrier copper foil can be prepared using the following steps: Step S1: Select electrolytic copper foil as a carrier and perform surface cleaning treatment.

[0031] The thickness of the selected electrolytic copper foil can be 12~70μm, for example, 18~30μm. Surface cleaning removes surface oil and oxide layers, exposing the fresh copper lattice.

[0032] Surface cleaning is the pretreatment of electrolytic copper foil, which includes pickling, rinsing with water, and drying with nitrogen. Dilute sulfuric acid can be used for pickling, and deionized water can be used for rinsing.

[0033] Step S2: Preparation of photosensitive precursor solution: Disperse conductive polymer monomer, nano-photocatalyst, and heat-resistant dopant in solvent, and ultrasonically treat to obtain a uniform dispersion.

[0034] This step imparts photosensitivity to the system through nano-photocatalysts and introduces aromatic sulfonate compounds (i.e., heat-resistant dopants) to give the polymer high-temperature resistance.

[0035] The conductive polymer monomer is selected from pyrrole, 3,4-ethylenedioxythiophene (EDOT), or aniline, with a concentration of 0.1~0.5 mol / L. The concentration of the conductive polymer monomer is further preferably 0.2~0.4 mol / L.

[0036] The photocatalyst nanoparticles are nano-titanium dioxide (TiO2), nano-zinc oxide (ZnO), or graphitic carbon nitride (g-C3N4). These photocatalysts utilize light energy to excite the catalyst to generate active species that initiate polymerization, exhibiting characteristics of non-contact reaction, mild reaction conditions, and strong controllability. The particle size of the photocatalyst nanoparticles is 10–50 nm, and the addition amount is 0.5–3.0% of the monomer mass. For example, it can be 1.0–2.0% of the monomer mass.

[0037] The aromatic sulfonate compound is selected from sodium 1,5-naphthalenedisulfonate, sodium anthraquinone sulfonate, or sodium polystyrene sulfonate. The concentration of the aromatic sulfonate compound is 0.05~0.2 mol / L.

[0038] Solvents such as water and aqueous ethanol solutions can be used, with the ethanol volume fraction in the aqueous ethanol solution being 20-50%. Add all materials to the solvent and disperse them evenly to form a milky white, homogeneous suspension. A uniformly dispersed photosensitive precursor solution can be quickly obtained using high-speed stirring, ultrasound, or other methods. Subsequently, the pH of the photosensitive precursor solution is fine-tuned to 3.0-6.0 using dilute sulfuric acid, for example, pH=4-6. Maintaining a slightly acidic environment helps to improve the reaction rate and film density of photocatalytically induced monomer (such as pyrrole, aniline, etc.) oxidative polymerization.

[0039] Step S3: Coat the photosensitive precursor liquid onto the surface of the electrolytic copper foil carrier, or immerse the carrier in the photosensitive precursor liquid, form a liquid film using the dip-coating method, and carry out a photocatalytic in-situ polymerization reaction under a light source of a specific wavelength. After cleaning and drying, a conductive polymer release layer is formed.

[0040] This step utilizes light energy to drive polymerization, completely avoiding the risk of "anodic corrosion" in electrochemical polymerization.

[0041] The liquid film can be irradiated under a light source in the wavelength range of 365nm to 450nm, such as ultraviolet light (UV, wavelength 365nm) or blue light (LED, wavelength 450nm), with a light intensity of 20~100 mW / cm². 2 The irradiation time is 30~120s. The in-situ polymerization of monomers on the support surface is initiated by electron-hole pairs or active free radicals generated by the photocatalyst.

[0042] Step S4: Without intermediate metallization treatment, an ultrathin copper layer is directly electroplated on the conductive polymer release layer to form a copper layer.

[0043] Because conductive polymers possess intrinsic conductivity, they can be directly used as cathodes for electroplating, eliminating the need for the expensive vacuum sputtering process. The current density for forming ultrathin copper layers during electroplating is 5~50 A / dm³. 2 The electroplating time is 1~3 min, and the thickness of the ultrathin copper layer is 1.5~5 μm.

[0044] The copper foil with a carrier prepared using the above method comprises a copper foil carrier layer, a conductive polymer release layer grown in situ on the surface of the copper foil carrier layer, and an ultrathin copper layer electrodeposited on the surface of the conductive polymer release layer. The conductive polymer release layer has the following characteristics: a film thickness of 30-150 nm, and is doped with nano-photocatalyst particles and heat-resistant dopants.

[0045] Based on this, the thickness of the carrier layer is 12~70μm, and the thickness of the ultrathin copper layer is 1.5~5μm; the normal peel strength is 0.2~0.4N / cm, and the peel strength change rate after 1h of heat aging at 260℃ is <20%.

[0046] The aforementioned carrier copper foil can be used as a lamination material in the semi-additive process (mSAP) for manufacturing high-density interconnect circuit boards with linewidth / spacing less than 30 / 30μm. During PCB fabrication, the carrier copper foil is laminated to a resin substrate, the carrier layer is peeled off, and the remaining ultrathin copper layer is used to create fine circuitry.

[0047] The implementation process of the present invention will be described in detail below with reference to specific embodiments. In the following embodiments, unless otherwise specified, the raw materials involved are all conventional commodities, and the processing techniques involved are all existing technologies. "%" refers to mass percentages.

[0048] Example 1 The method for preparing the carrier copper foil in this embodiment adopts the following steps: Step 1: Select an 18μm thick electrolytic copper foil, acid-wash it with dilute sulfuric acid, rinse it with deionized water, and dry it with nitrogen gas for later use. During the acid-washing process, the concentration of dilute sulfuric acid is 50g / L, and the treatment time is 30s.

[0049] Step 2: Prepare the photosensitizing precursor solution. Weigh pyrrole monomer (0.2 mol / L), nano TiO2 (P25, particle size 21 nm, added at 1.0 wt% of monomer mass), and sodium 1,5-naphthalenedisulfonate (0.05 mol / L), and dissolve / disperse them in a mixed solvent of deionized water and ethanol (volume ratio 4:1). Sonicate the solution for 30 min to obtain a milky white homogeneous suspension. Adjust the pH of the suspension to approximately 4.0 by adding 5% dilute sulfuric acid dropwise.

[0050] Step 3: Immerse the copper foil in the precursor solution using the dip-coating method at a speed of 5 mm / s to form a uniform liquid film on the copper foil surface. Then place it under a UV LED light source (wavelength 365 nm, intensity 50 mW / cm²). 2 The copper foil was vertically irradiated for 60 seconds. Under irradiation, TiO2 was stimulated to generate electron-hole pairs, initiating pyrrole oxidative polymerization, and the copper foil surface rapidly turned a uniform dark black. After the reaction, unreacted monomers were removed by rinsing with ethanol, and the foil was dried at 60°C.

[0051] Step 4: Place the copper foil with the polypyrrole release layer in an acidic copper plating solution with a current density of 20 A / dm². 2 Electroplating for 2 minutes yielded an ultrathin copper layer with a thickness of 2 μm. The acidic copper plating solution consisted of: CuSO4·5H2O 200 g / L, H2SO4 60 g / L, chloride ions 60 mg / L, polyethylene glycol 300 mg / L, and deionized water as the solvent.

[0052] The copper foil with a support obtained in this embodiment includes a stacked electrolytic copper foil support, a polypyrrole release layer grown in situ on the electrolytic copper foil support, and an ultrathin copper layer electrodeposited on the polypyrrole release layer. The thickness of the electrolytic copper foil support is 18 μm, the thickness of the polypyrrole release layer is 80 nm, and the thickness of the ultrathin copper layer is 2 μm. The polypyrrole release layer includes polypyrrole and nano-TiO2 and sodium 1,5-naphthalenedisulfonate doped in the polypyrrole.

[0053] Example 2 The method for preparing the carrier copper foil in this embodiment is the same as in Example 1, except that: The monomer was replaced with 3,4-ethylenedioxythiophene (EDOT) at a concentration of 0.1 mol / L; the photocatalyst was replaced with nano-ZnO with a particle size of 30 nm, added at 2.0 wt% of the monomer mass. The illumination time was extended to 90 s. The remaining steps were the same as in Example 1.

[0054] The carrier copper foil in this embodiment is a PEDOT conductive release layer carrier copper foil. The difference in structure between this and the carrier copper foil in Example 1 is that the thickness of its intermediate release layer is 60 nm. This intermediate release layer comprises poly(3,4-ethylenedioxythiophene) and nano-ZnO and sodium 1,5-naphthalenedisulfonate doped in poly(3,4-ethylenedioxythiophene).

[0055] Example 3 The method for preparing the carrier copper foil in this embodiment is the same as in Example 1, except that: When preparing the photosensitive precursor solution, ethanol is not added, and pure water is used as the solvent; the heat-resistant dopant is replaced with sodium polystyrene sulfonate (PSS). The remaining steps are the same as in Example 1.

[0056] The difference between the carrier copper foil in this embodiment and that in Embodiment 1 is that the heat-resistant dopant in the intermediate release layer is sodium polystyrene sulfonate.

[0057] Example 4 The preparation method of the carrier copper foil in this embodiment is the same as that in Example 1, except that: Step 1: Select an electrolytic copper foil with a thickness of 12μm as the carrier.

[0058] Step 2: Prepare the photosensitizing precursor solution. Weigh aniline monomer (0.1 mol / L), graphitic carbon nitride (g-C3N4, particle size 10 nm, added at 0.5 wt% of monomer mass), and sodium anthraquinone sulfonate (0.05 mol / L) and dissolve / disperse them in a solvent (same as in Example 1), and adjust the pH of the system to 6.

[0059] Step 3: The dip-coating method was used, with the coating speed controlled at 3 mm / s. The substrate was then vertically irradiated under a blue light source (wavelength 450 nm, intensity 20 mW / cm²) for 30 s. The thickness of the in-situ grown conductive polymer release layer was measured to be approximately 30 nm.

[0060] Step 4: When electroplating to form an ultra-thin copper layer, control the current density to 5 A / dm³. 2 The electroplating time was 1 min, resulting in an ultrathin copper layer with a thickness of approximately 1.5 μm.

[0061] Example 5 The preparation method of the carrier copper foil in this embodiment is the same as that in Example 1, except that: Step 1: Select an electrolytic copper foil with a thickness of 70μm as the carrier.

[0062] Step 2: Prepare the photosensitizing precursor solution. Weigh 3,4-ethylenedioxythiophene monomer (EDOT, 0.5 mol / L), nano zinc oxide (ZnO, particle size 50 nm, added at 3.0 wt% of monomer mass), and sodium polystyrene sulfonate (0.2 mol / L) and dissolve / disperse them in a solvent (same as in Example 1), and adjust the pH of the system to 5.

[0063] Step 3: Use the dip-lift method, controlling the lifting speed at 5mm / s. Then place it under a UV light source (wavelength 365nm, intensity 100 mW / cm²). 2 The material was vertically irradiated for 120 seconds. The thickness of the in-situ grown conductive polymer exfoliation layer was measured to be approximately 150 nm.

[0064] Step 4: When electroplating to form an ultra-thin copper layer, control the current density to 50 A / dm³. 2 The electroplating time was 3 minutes, resulting in an ultrathin copper layer with a thickness of approximately 5.0 μm.

[0065] Example 6 The preparation method of the carrier copper foil in this embodiment is the same as that in Example 1, except that: Step 2: Prepare the photosensitizing precursor solution. Weigh pyrrole monomer (0.3 mol / L), nano titanium dioxide (TiO2, particle size 30 nm, added at 1.5 wt% of monomer mass), and sodium 1,5-naphthalenedisulfonate (0.1 mol / L) and dissolve / disperse them in a solvent (same as in Example 1), and adjust the pH of the system to 3.

[0066] Step 3: Using a coating method (such as wire rod coating or microgravure coating), uniformly coat the photosensitive precursor solution onto the surface of the carrier copper foil to form a liquid film. Then place it under a UV light source, controlling the intensity at 50 mW / cm². 2 Irradiation was performed for 60 seconds. The thickness of the in-situ grown conductive polymer release layer was measured to be approximately 80 nm.

[0067] Step 4: Control the current density to 25 A / dm 2 The electroplating time was 2 minutes, resulting in an ultrathin copper layer with a thickness of approximately 3.0 μm.

[0068] (II) Experimental Examples Experimental Example 1 In Example 1, physical images of the carrier copper foil, release layer, and ultra-thin copper foil are shown below. Figure 1 As shown.

[0069] The SEM image of the polypyrrole release layer is shown below. Figure 2 As shown, by Figure 2 It can be seen that the in-situ grown conductive polymer release layer exhibits a unique sheet-like / scale-like microstructure, and the film surface is accompanied by fine wrinkles and microcracks. The intermediate peeling layer with this morphology has the following significant process advantages: 1. Constructing a natural fracture guiding zone: The microcracks and flaky edges distributed on the surface can serve as natural weak points for stress concentration during mechanical peeling, greatly reducing tearing resistance and ensuring that the peeling strength remains stable within the ideal range for easy operation (0.2~0.4 N / cm), achieving precise and smooth peeling; 2. Moderate mechanical interlocking: The flaky micro-rough structure provides sufficient "grip" for the subsequently deposited ultrathin copper layer, forming a slight physical-mechanical interlock, ensuring that the ultrathin copper layer will not blister or fall off during subsequent complex wet processing (such as development and etching); 3. Effective metal isolation: Although there are cracks and wrinkles on the surface, the underlying polymer film still continuously covers the carrier copper foil substrate (concealing the processing texture of the substrate), successfully blocking large-area direct contact between the ultrathin copper layer and the underlying carrier copper, completely eliminating the "spot welding" deadlock phenomenon between metals.

[0070] EDS characterization results of the polypyrrole exfoliation layer are as follows Figure 3 As shown, by Figure 3 As can be seen, C (carbon) and N (nitrogen) elements exhibit a highly uniform and dense distribution throughout the scanning area. This result fully confirms the in-situ uniform growth of the conductive polymer film of the present invention: the dense and uniformly distributed C and N element signals directly confirm that the nitrogen-containing conductive polymer (such as polypyrrole) underwent a complete and uniform polymerization reaction on the surface of the carrier copper foil, without any obvious agglomeration or missing areas.

[0071] FTIR analysis of the polypyrrole release layer yielded the following results: Figure 4 As shown. Figure 4 The mid-infrared spectral characteristic peak analysis results show that: 1535 cm⁻¹ -1 and 1447 cm -1 The absorption peaks at 1069 cm⁻¹ correspond to the C=C and C=C stretching vibrations of the pyrrole ring, respectively. -1 The absorption peak at 886 cm⁻¹ is attributed to the characteristic peak of CN stretching vibration. -1 With 789 cm -1 The absorption peaks at these locations correspond to the out-of-plane deformation vibration and out-of-plane bending vibration of CH, respectively. These infrared characteristic peaks are in perfect agreement with the structural characteristics of polypyrrole (PPy), confirming that the synthesized product is polypyrrole.

[0072] SEM image of ultrathin copper foil as shown Figure 5 As shown. By Figure 5 As can be seen, the ultrathin copper foil prepared by this invention exhibits a highly dense, flat, and extremely fine microstructure, without any obvious pinholes, cracks, or abnormally large nodules. The ultrathin copper foil prepared by this invention has the following significant advantages: 1. Uniform nucleation and high density: Thanks to the excellent intrinsic conductivity of the conductive polymer film grown in situ at the bottom layer, the problem of uneven local current distribution caused by the reliance on tunneling effect in traditional insulating organic release layers is completely overcome, realizing uniform and rapid nucleation and growth of copper ions on the entire cathode surface; 2. Perfect etching adaptability: The nanoscale fine crystalline structure shown in the figure (especially Figure a) endows the ultrathin copper layer with extremely low surface roughness and excellent microstructure uniformity.

[0073] Experimental Example 2 The copper foil with carrier prepared in the above embodiments was subjected to peel strength tests under normal conditions and peel strength tests after 1 hour of heat aging at 260°C, in accordance with the printed circuit board industry standard IPC-TM-650 2.4.8. The specific test parameters and procedures were as follows: the ultra-thin copper layer surface of the copper foil with carrier was bonded to a high TgFR-4 epoxy resin prepreg, and the copper-clad laminate was formed by lamination under conventional lamination conditions (temperature 190°C, pressure 3.0MPa) for 90 minutes; then it was cut into standard strips with a width of 10mm.

[0074] Normal peel force test: Using a universal tensile testing machine, the metal carrier layer is peeled uniformly from the copper-clad laminate at a tensile speed of 50 mm / min along a 90-degree direction, and the average peel force is recorded. Post-heat aging peel force test: The copper-clad laminate sample prepared by lamination is placed in a constant temperature drying oven at 260℃ for 1 hour. After being removed and naturally cooled to room temperature, it is tested under the same 90-degree peel conditions as under normal conditions.

[0075] The test results for each embodiment are as follows: The normal peel strength of the copper foil with carrier in Example 1 was 0.35 N / cm; after 260℃ / 1h, it was 0.38 N / cm, and the peel rate change rate was 8.57%.

[0076] The normal peel strength of the copper foil with carrier in Example 2 was 0.28 N / cm; after 260℃ / 1h, it was 0.30 N / cm, and the peel rate change rate was 7.14%.

[0077] The normal peel strength of the copper foil with carrier in Example 3 was 0.42 N / cm; after 260℃ / 1h, it was 0.48 N / cm, and the peel rate change rate was 14.29%.

[0078] Example 4 test results: The normal peel force was 0.21 N / cm; after 260℃ / 1h, it was 0.23 N / cm, and the peel rate change rate was 9.5% (the peel layer was thin and the peel force was low, but it met the requirements).

[0079] Example 5 test results: The normal peel force was 0.39 N / cm; after 260℃ / 1h, it was 0.46 N / cm, and the peel rate change rate was 17.9% (the film layer reached its thickest point, the peel force was relatively high, but it was still qualified).

[0080] Example 6 test results: The normal peel force was 0.33 N / cm; after 260℃ / 1h, it was 0.36 N / cm, and the peel rate change rate was 9.1%.

[0081] (III) Comparative Example Comparative Example 1 (without photocatalyst) In this comparative example, no nano-TiO2 was added to the photosensitive precursor solution during the preparation of the carrier copper foil; otherwise, the process was the same as in Example 1.

[0082] The results showed that after 60 seconds of UV irradiation, the copper foil surface did not undergo significant color change, and no effective polymer film was formed. Subsequent electroplating deposited directly onto the copper carrier, resulting in irremovable peeling (peeling force >10 N / cm, forming an integrated copper plate). This demonstrates that the photocatalyst is key to initiating polymerization.

[0083] Comparative Example 2 (without heat-resistant dopants) In this comparative example, sodium 1,5-naphthalenedisulfonate was not added to the photosensitive precursor solution during the preparation of the carrier copper foil; only dilute sulfuric acid was used to adjust the pH of the precursor solution to 4.0.

[0084] The results showed that the normal peel strength of the obtained copper foil with the carrier was 0.32 N / cm, indicating good peel performance. However, after heat treatment at 260℃ for 1h, the peel strength increased to 1.5 N / cm, and black carbonized residue was present at the peel interface. This demonstrates that aromatic sulfonates are crucial for high-temperature resistance and are an important factor in preventing PCB high-temperature peel lock-up.

[0085] As can be seen from the above examples and comparative examples, this method adopts a full-process synergistic process of "preparation of photosensitive precursor solution - photoinduced in-situ polymerization - direct electrodeposition of ultrathin copper". The in-situ grown conductive polymer release layer carrier copper foil has a normal peel force and a high temperature peel force in the ideal range. The quality of the ultrathin copper layer is good and it can be used as a lamination material in the semi-additive process (mSAP) for manufacturing high-density interconnect circuit boards with line width / spacing less than 30 / 30μm.

[0086] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A carrier-attached copper foil comprising a metal carrier layer, characterized by, A conductive polymer release layer is grown in situ on the surface of the metal carrier layer. The conductive polymer release layer includes a conductive polymer, nano-photocatalyst particles doped in the conductive polymer, and an aromatic sulfonate compound. The nano-photocatalyst particles are formed into the conductive polymer through photocatalytic monomer polymerization. The aromatic sulfonate compound improves the heat resistance of the conductive polymer to prevent the release layer from carbonizing at the PCB lamination temperature. An ultrathin copper layer is electrodeposited on the conductive polymer release layer.

2. The carrier-carrying copper foil according to claim 1, wherein The thickness of the conductive polymer exfoliating layer is 30~150nm, and the particle size of the nano-photocatalyst particles is 10~50nm; the nano-photocatalyst particles are nano-titanium dioxide, nano-zinc oxide, or graphitic carbon nitride.

3. The carrier-carrying copper foil according to claim 1, wherein The aromatic sulfonate compound is sodium 1,5-naphthalene disulfonate, sodium anthraquinone sulfonate, or sodium polystyrene sulfonate.

4. The carrier-carrying copper foil according to any one of claims 1 to 3, wherein, The total thickness of the copper foil with the carrier is 15~75μm, of which the thickness of the metal carrier layer is 12~70μm and the thickness of the ultrathin copper layer is 1.5~5μm; the normal peel force of the copper foil with the carrier is 0.2~0.4N / cm, and the peel force change rate after heat aging at 260℃ for 1h is <20%, or <10%.

5. The carrier-copper foil according to any one of claims 1 to 3, wherein The monomer is pyrrole, 3,4-ethylenedioxythiophene, or aniline.

6. A method of producing a carrier-copper foil according to any one of claims 1 to 5, characterized by, Includes the following steps: A photosensitive precursor solution is prepared by using conductive polymer monomers, nano-photocatalysts, aromatic sulfonate compounds and solvents. The photosensitive precursor solution is coated on a pretreated metal foil carrier to form a liquid film. Then, a conductive polymer release layer is formed by photocatalytic in-situ polymerization. Finally, an ultrathin copper layer is formed by electroplating on the conductive polymer release layer.

7. The method for producing a carrier-copper foil according to claim 6, wherein In the photosensitive precursor solution, the concentration of the conductive polymer monomer is 0.1~0.5 mol / L, the added mass of the nano-photocatalyst is 0.5~3.0% of the monomer mass; the concentration of the aromatic sulfonate compound is 0.05~0.2 mol / L; and the pH is 3.0~6.

0.

8. The method for producing a carrier-copper foil according to claim 7, wherein The coating is performed using either a dip-coating method or a coating method, wherein the dip-coating method has a lifting speed of 3~5 mm / s.

9. The method for preparing the carrier copper foil as described in claim 6 or 7, characterized in that, During the photocatalytic in-situ polymerization, ultraviolet or blue light source irradiation is used, with a light intensity of 20~100mW / cm². 2 The irradiation time is 30~120s.

10. The method for producing a carrier-copper foil according to claim 6 or 7 or 8, characterized in that, The current density for forming the ultrathin copper layer by electroplating is 5~50A / dm. 2 The electroplating time is 1~3 min, and the thickness of the ultrathin copper layer is 1.5~5 μm.

Images