Method for producing a supported ultrathin metal foil

Abstract

The application relates to the technical field of metal materials, and discloses a preparation method of a carrier-equipped ultrathin metal foil, wherein the carrier-equipped ultrathin metal foil comprises a carrier foil, a metal stripping layer, an organic stripping layer and an ultrathin metal foil which are sequentially stacked, the preparation method comprises the following steps: 1) performing surface treatment on at least one side of the carrier foil; 2) forming a metal stripping layer on the surface of the carrier foil subjected to the surface treatment through electrodeposition; wherein the metal stripping layer comprises at least one element selected from chromium, nickel, cobalt, iron, copper and titanium; 3) immersing the carrier foil comprising the metal stripping layer into an organic stripping layer solution to perform ultrasonic treatment, so as to form the organic stripping layer; and 4) forming the ultrathin metal foil on the surface of the organic stripping layer. By adopting the composite stripping layer and introducing ultrasonic treatment when the organic stripping layer is formed, the speed of forming the organic stripping layer is faster, the film layer thickness is more uniform, the stripping stability can be improved, and the production efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of metal materials technology, and in particular to a method for preparing an ultrathin metal foil with a carrier. Background Technology

[0002] Electrolytic copper foil, as a key basic material, is widely used in modern technology fields such as chip packaging, printed circuit boards, and new energy equipment. With the increasing demand for high-density integrated circuits and lightweight power batteries, higher requirements are being placed on the thickness and performance of copper foil. Especially in the preparation of extremely thin copper foil, it is easily affected by external forces, resulting in wrinkles or tears.

[0003] To overcome these problems, the industry has abandoned conventional methods of manufacturing copper foil and creatively proposed a technology for preparing ultra-thin carrier copper foil. Because of the support provided by the carrier, issues such as wrinkling or tearing during transportation and storage can be resolved. Preparing ultra-thin copper foil using a carrier-attached method requires forming a release layer between the carrier foil and the ultra-thin copper foil, facilitating easy tearing after lamination.

[0004] Existing release layers typically include inorganic release layers, organic release layers, and composite release layers. Inorganic release layers generally consist of metal or alloy layers, offering advantages such as good stability at high temperatures. However, diffusion between the metal layer and the copper foil enhances the interfacial adhesion, leading to separation difficulties. Organic release layers achieve good separation, but uneven release strength affects the stability of extremely thin copper foils. Composite release layers combine the advantages of both inorganic and organic release layers, but the primary preparation method for organic release layers remains static dip-coating. This method relies on passive diffusion and natural adsorption, resulting in slow film formation, poor film uniformity, and low preparation efficiency, failing to meet the efficiency and quality requirements of modern production. Therefore, process innovation or equipment improvement is urgently needed to enhance production efficiency and quality. Summary of the Invention

[0005] Based on this, the main objective of this application is to provide a method for preparing an ultrathin metal foil with a carrier, which uses ultrasonic treatment to form an organic release layer, thereby solving the problems of uneven organic release layer and low efficiency in the current preparation process of ultrathin metal foil with a carrier, thus ensuring the release stability of the organic release layer and improving production efficiency.

[0006] To achieve the above objectives, embodiments of the present invention provide a method for preparing an ultrathin metal foil with a carrier, wherein the ultrathin metal foil with a carrier comprises a carrier foil, a metal release layer, an organic release layer, and an ultrathin metal foil stacked sequentially, and the method for preparing the ultrathin metal foil with a carrier includes the following steps:

[0007] 1) A metal release layer is formed by electrodeposition on the surface of a carrier foil; wherein the metal release layer comprises at least one element selected from chromium, nickel, cobalt, iron, copper and titanium;

[0008] 2) The carrier foil containing the metal release layer is immersed in an organic release layer solution and subjected to ultrasonic treatment to form an organic release layer;

[0009] 3) An extremely thin metal foil is formed on the surface of the organic peeling layer.

[0010] In one embodiment, before electrodepositing to form a metal release layer, at least one side of the carrier foil in step 1) is surface treated, the surface treatment including at least one of polishing, deoxidation, and degreasing.

[0011] In one embodiment, the surface treatment of the carrier foil is performed sequentially using acetone, anhydrous ethanol, and 10 vol.% dilute sulfuric acid.

[0012] In one embodiment, the metal stripping layer in step 1) is nickel.

[0013] In one embodiment, the electrolyte for electrodeposition of the metallic nickel comprises nickel sulfate hexahydrate at a concentration of 50-300 g / L, boric acid at a concentration of 20-120 g / L, and chloride at a concentration of 20-120 g / L; the electrolyte temperature is 20-70°C, and the current density is 5-30 A / dm³. 2 Electrolysis time: 10-200s.

[0014] In one embodiment, the organic stripping layer in step 2) comprises at least one of purine organic compounds and derivatives of purine organic compounds.

[0015] In one embodiment, the organic peeling layer includes at least one substance selected from adenine, guanine, xanthine, hypoxanthine, caffeine, and theophylline.

[0016] In one embodiment, the concentration of the organic exfoliating layer is 0.1 g / L to 10 g / L.

[0017] In one embodiment, the ultrasonic frequency of the ultrasonic treatment in step 2) is 10-150kHz, the ultrasonic power is 10-150W, and the immersion time is 10-3000s.

[0018] In one embodiment, the carrier foil containing the metal stripping layer in step 2) is 2-20 cm away from the bottom of the organic stripping layer solution.

[0019] In one embodiment, the ultra-thin metal foil in step 3) is an ultra-thin copper foil, which is formed by electrodeposition using an electrolyte with a copper concentration of 50-110 g / L, a sulfuric acid concentration of 80-120 g / L, a chloride concentration of 20-50 ppm, a hydroxyethyl cellulose concentration of ≤20 ppm, and a gelatin concentration of ≤40 ppm; the electrolyte temperature is 20-70°C, and the current density is 5-30 A / dm³. 2 Electrolysis time: 10-200s.

[0020] Compared with existing technologies, the advantages of this invention are as follows: By electrodepositing a metal release layer on the surface of a carrier foil, and then coating the surface of the metal release layer with an organic release layer solution to form an organic release layer, a composite release layer is prepared. This allows the metal release layer to form a strong interfacial bond with the carrier foil, while the organic release layer forms a weaker interfacial bond with the ultra-thin metal foil, achieving differentiated control of interfacial strength and enabling the ultra-thin metal foil to be released. Simultaneously, ultrasonic treatment is introduced during the preparation process of the organic release layer coating to promote the formation of the organic release layer, resulting in a faster formation speed, a thicker and more uniform film layer, higher production efficiency, improved release stability, and increased production efficiency. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings are only for illustrating preferred embodiments and are not intended to limit this application. Throughout the drawings, the same reference numerals denote the same parts. In the drawings:

[0022] Figure 1 This is a flowchart illustrating the steps of a method for preparing an ultrathin metal foil with a carrier according to an embodiment of the present invention.

[0023] Figure 2 This is a flowchart of the surface treatment steps of the carrier foil according to an embodiment of the present invention;

[0024] Figure 3 This is a schematic diagram of the structure of an ultrathin metal foil with a carrier according to an embodiment of the present invention.

[0025] Among them, 1. carrier foil; 2. composite release layer; 21. metal release layer; 22. organic release layer; 3. ultra-thin metal foil; 4. anti-oxidation layer. Detailed Implementation

[0026] 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 some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] In the description of the specification and claims, it should be understood that the terms "upper", "lower", "left", "right", "front", "rear", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the embodiments of the present invention, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the embodiments of the present invention.

[0028] Furthermore, the terms "first," "second," etc., used in the specification and claims are used only to distinguish the description of the same technical features and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated, nor necessarily the order of description or chronological sequence. Where appropriate, the terms are interchangeable. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature.

[0029] See Figure 1 , Figure 1 This diagram illustrates a step-by-step flowchart of a method for preparing a carrier-supported ultrathin metal foil according to an embodiment of the present invention. The carrier-supported ultrathin metal foil includes a carrier foil 1, a metal release layer 21, an organic release layer 22, and an ultrathin metal foil 3 (e.g., ...) stacked sequentially. Figure 3 The method for preparing the carrier-supported ultrathin metal foil includes the following steps:

[0030] S10: Electrodeposit a metal release layer 21 on the surface of the carrier foil 1; wherein the metal release layer 21 includes at least one element selected from chromium, nickel, cobalt, iron, copper and titanium;

[0031] S20: Immerse the carrier foil containing the metal release layer into the organic release layer solution and perform ultrasonic treatment to form the organic release layer 22;

[0032] S30: An extremely thin metal foil 3 is formed on the surface of the organic release layer.

[0033] The above-mentioned method for preparing ultrathin metal foil with a carrier involves electrodepositing a metal release layer 21 on the surface of a carrier foil 1, then coating the surface of the metal release layer 21 with an organic release layer solution to form an organic release layer 22, thus preparing a composite release layer 2. This allows the metal release layer 21 to form a strong interfacial bond with the carrier foil 1, while the organic release layer 22 forms a weaker interfacial bond with the ultrathin metal foil 3, achieving differentiated control of interfacial strength and enabling the ultrathin metal foil 3 to be released. Simultaneously, during the preparation of the organic release layer 22, ultrasonic treatment is introduced. Ultrasonic waves induce high-frequency vibrations in the liquid, generating microscale turbulence, breaking the surface tension constraints of the solution, and spreading into a film. The ultrasonic waves generate periodic pressure changes in the liquid, forming tiny vacuum bubbles. These bubbles expand during negative pressure periods and collapse violently during positive pressure periods, generating localized high pressure and high-speed microjets that scour the surface of the carrier foil, removing adsorbed bubbles and contaminants, and enhancing the uniformity of the release material's adhesion. Simultaneously, cavitation energy can break the oxide layer on the surface of the carrier foil, exposing fresh active sites and promoting the chemical bonding of the release layer molecules. This promotes the formation of the organic release layer, making the organic release layer form faster, the film layer thicker and more uniform, and the production efficiency higher. It can also improve the release stability and increase production efficiency.

[0034] It should be noted that the carrier foil 1 serves a bearing function, used to support the extremely thin metal foil 3. The thickness of the carrier foil 1 is 12~50 micrometers. The material of the carrier foil 1 can be any one of zinc, iron, aluminum, cobalt, copper, titanium, nickel, chromium, silver and gold.

[0035] In one embodiment, before electrodepositing the metal release layer 21, at least one side of the carrier foil 1 undergoes surface treatment, which includes at least one of polishing, oxide layer removal, and degreasing. Surface treatment of the carrier foil 1 optimizes its surface condition, facilitating the preparation of a uniform and dense release layer. Polishing involves mechanically grinding to remove surface material or selectively dissolving microscopic protrusions using electrolytic polishing to achieve atomic-level smoothness. Oxide layer removal utilizes acid etching to dissolve oxides or electrochemical reduction to directly remove the oxide layer, removing the insulating barrier, improving the conductivity of the carrier foil, and facilitating the electrodeposition of the metal release layer. Simultaneously, the newly formed metal surface has high chemical activity, making it easier to form chemical bonds with the metal release layer. Degreasing utilizes organic solvents to dissolve non-polar contaminants or uses alkaline degreasing solutions to saponify grease, forming water-soluble substances, eliminating organic contaminants, and removing organic matter such as grease, fingerprints, and rust inhibitors adsorbed during production, transportation, or storage. This increases surface energy and prevents the formation of a weak interface layer between the carrier foil and the metal release layer, which would facilitate delamination. The above methods can also be combined to form a uniform metal release layer on the surface of the carrier foil.

[0036] See Figure 2 , Figure 2A flowchart illustrating the surface treatment steps of the carrier foil according to an embodiment of the present invention is shown. The surface of the carrier foil is treated sequentially with acetone, anhydrous ethanol, and 10 vol.% dilute sulfuric acid, specifically including:

[0037] S111: Immerse the carrier foil in acetone to clean it, then remove it and dry it with nitrogen gas.

[0038] S112: Immerse the carrier foil in anhydrous ethanol for cleaning;

[0039] S113: Immerse in 10 vol.% dilute sulfuric acid at room temperature, rinse thoroughly with deionized water, and dry with nitrogen or vacuum.

[0040] In this embodiment of the invention, the carrier foil 1 is immersed in acetone for 5–10 minutes to remove organic contaminants. Acetone, as a non-polar solvent, can effectively dissolve most organic impurities. It is then removed and dried with nitrogen. To remove acetone residue and polar contaminants, the carrier foil is immersed in anhydrous ethanol for 3–5 minutes for further cleaning. Ethanol, possessing both polar and non-polar groups, can remove residual organic matter and dehydrate the surface. Finally, it is soaked in 10 vol.% dilute sulfuric acid at room temperature for 10–60 seconds to remove the oxide layer and activate the metal surface. After removal, it is rinsed with plenty of deionized water to terminate the reaction and dried with nitrogen or under vacuum at 80°C for 1 hour to prevent re-oxidation. This treatment method can efficiently prepare a clean, low-oxidation, and highly active carrier foil 1 surface, suitable for the stable and uniform deposition of the metal release layer 21.

[0041] It should be noted that the composite release layer 2 used in this embodiment of the invention includes an inorganic release layer and an organic release layer. The inorganic release layer is generally composed of a metal layer or an alloy layer, which has the advantage of good stability at high temperatures, but the diffusion between the metal layer and the copper foil enhances the adhesion strength at the interface, making separation difficult; the organic release layer can achieve good separation, but the peel strength is uneven, affecting the stability of the extremely thin metal foil; the composite release layer combines the advantages of the inorganic release layer and the organic layer of the organic release layer.

[0042] In one embodiment, step S10: the metal release layer 21 is metallic nickel. The interfacial adhesion between nickel and the ultra-thin metal foil 3 is moderate and easily controlled. By adjusting the nickel plating process, the bonding strength between the nickel layer and the ultra-thin metal foil can be precisely controlled, ensuring that it does not fall off during processing and can be easily peeled off mechanically or chemically during use, thus resolving the contradiction between "firmness" and "ease of peeling". At the same time, nickel has a high melting point, so it will not be damaged or fail due to high-temperature softening or oxidation during the high-temperature processing of the ultra-thin metal foil with a carrier.

[0043] Furthermore, the electrolyte for electrodeposition of the metallic nickel comprises nickel sulfate hexahydrate with a concentration of 50-300 g / L, boric acid with a concentration of 20-120 g / L, and chloride with a concentration of 20-120 g / L; the electrolyte temperature is 20-70℃, and the current density is 5-30 A / dm³. 2 The electrolysis time is 10-200 seconds. Under these process conditions, a dense and uniform thickness of metallic nickel is deposited on the surface of the carrier foil, forming a stable peel.

[0044] In one embodiment, the organic stripping layer 22 in step S20 comprises at least one substance selected from purine organic compounds and derivatives of purine organic compounds. Purine organic compounds and derivatives of purine organic compounds, as organic stripping layers, can achieve stripping effects with a single layer or multiple molecular layers, providing gentle stripping and reducing damage to the extremely thin metal foil. The amino groups of purines form weak hydrogen bonds with the carrier foil, rather than strong chemical bonds, facilitating mechanical separation. Preferably, the organic stripping layer comprises at least one substance selected from adenine, guanine, xanthine, hypoxanthine, caffeine, and theophylline.

[0045] In one embodiment, the concentration of the organic release layer 22 is 0.1 g / L to 10 g / L. Limiting the concentration of the organic release layer 22 to this range improves the release effect. Too low a concentration results in poor film formation of the organic release layer 22, leading to incomplete release and damage to the extremely thin metal foil; too high a concentration results in low release strength, easy delamination, and hinders processing and use. Therefore, limiting the concentration of the organic release layer to 0.1 g / L to 10 g / L ensures smooth release without detachment. Optionally, the concentration of the organic release layer can be any value or a range of any two values ​​from 0.1 g / L, 0.5 g / L, 1 g / L, 2 g / L, 3 g / L, 5 g / L, 7 g / L, 8 g / L, or 10 g / L.

[0046] It is worth noting that in this embodiment of the invention, the organic release layer 22 is formed by dip coating. The carrier foil 1 is immersed in a solution containing the organic release layer 22, then slowly pulled up. The pulled wet film is dried to evaporate the solvent, leaving a uniform organic release layer 22. During the preparation of the dip-coated organic release layer 22, ultrasonic treatment is introduced. The ultrasonic waves induce high-frequency vibrations in the liquid, generating microscale turbulence, breaking the surface tension constraints of the solution, and spreading into a film. The ultrasonic waves generate periodic pressure changes in the liquid, forming tiny vacuum bubbles. These bubbles expand during negative pressure periods and collapse violently during positive pressure periods, generating localized high pressure and high-speed microjets that scour the surface of the carrier foil, removing adsorbed bubbles and contaminants, and enhancing the uniformity of the release material's adhesion. Simultaneously, cavitation energy can break the oxide layer on the surface of the carrier foil, exposing fresh active sites and promoting the chemical bonding of the release layer molecules. This further promotes the formation of the organic release layer 22, resulting in a faster formation speed, a thicker and more uniform film, higher production efficiency, improved release stability, and increased production efficiency.

[0047] Preferably, the ultrasonic frequency of the ultrasonic treatment in step S20 is 10-150 kHz, the ultrasonic power is 10-150 W, and the immersion time is 10-3000 s. By setting the process parameters of the ultrasonic treatment within the above range, on the one hand, it avoids the situation where the ultrasonic frequency or ultrasonic power is too low, resulting in insufficient frequency and intensity of liquid vibration caused by the ultrasonic waves, making it difficult to break the surface tension of the solution and causing the organic release layer to be difficult to spread and form a film, thus affecting the smooth peeling of the ultra-thin metal foil with the carrier; on the other hand, it avoids the situation where the ultrasonic frequency or ultrasonic power is too high, resulting in the organic release layer being difficult to adhere to the surface of the metal release layer, resulting in low peel strength, easy delamination, and affecting the subsequent processing and application of the ultra-thin metal foil. Therefore, setting the process parameters of the ultrasonic treatment within the above range ensures that the organic release layer forms a film quickly, ensuring that the organic release layer is evenly spread on the surface of the metal release layer, forming a uniform and stable composite release layer, ensuring the complete peeling of the ultra-thin metal foil with the carrier, and high production efficiency, meeting the requirements of quality and efficiency.

[0048] Furthermore, in step S20, the carrier foil 1 of the metal release layer 21 is 2-20 cm away from the bottom of the organic release layer solution. Controlling the distance between the carrier foil and the bottom of the solution within this range during the dip-coating method for preparing the organic release layer is beneficial for forming a uniform organic release layer. On the one hand, it prevents the organic release layer solution from forming sediment at the bottom of the container due to density or solubility differences, which could then touch the carrier foil, resulting in an uneven organic release layer, or from bubbles rising due to ultrasound, affecting the uniformity of the organic release layer. On the other hand, it prevents the micro-scale turbulence generated by high-frequency vibrations of the liquid due to ultrasound from being too far from the bottom, which would make it difficult for the surface tension of the solution to be broken, hindering the organic release layer from spreading and forming a film, and thus affecting the smooth peeling of the extremely thin metal foil with the carrier. Therefore, a distance of 2-20 cm between the carrier foil and the bottom of the solution allows the organic release layer to spread evenly on the surface of the metal release layer, forming a uniform and stable composite release layer. This ensures a strong interfacial bond between the metal release layer and the carrier foil, while a weaker interfacial bond is formed between the organic release layer and the ultra-thin metal foil. This differentiated control of interfacial strength enables the ultra-thin metal foil to be peeled off. Preferably, in step S20, the carrier foil containing the metal release layer is 5-15 cm from the bottom of the organic release layer solution.

[0049] It should be noted that the ultra-thin metal foil 3 is used to fabricate circuits. The thickness of the ultra-thin metal foil 3 is 1 to 6 micrometers, and the material of the ultra-thin metal foil 3 can be any one of aluminum, titanium, zinc, iron, nickel, chromium, cobalt, copper, silver, and gold.

[0050] In one embodiment, the ultrathin metal foil 3 in step S30 is an ultrathin copper foil, which is formed by electrodeposition using an electrolyte with a copper concentration of 50-110 g / L, a sulfuric acid concentration of 80-120 g / L, a chloride concentration of 20-50 ppm, a hydroxyethyl cellulose concentration of ≤20 ppm, and a gelatin concentration of ≤40 ppm; the electrolyte temperature is 20-70°C, and the current density is 5-30 A / dm³. 2 Electrolysis time is 10-200s. Through this electrolyte formulation and electrodeposition process, multi-component synergistic regulation and wide parameter window adaptation, precise control of ultra-thin copper foil thickness is achieved. The ultra-thin copper foil has high strength, low internal stress, and no pinholes, better meeting the high-end needs of lithium batteries, electronic circuits and other fields.

[0051] It is worth noting that the ultrathin metal foil with a carrier also includes an antioxidant layer 4 (such as...). Figure 3The antioxidant layer 4 is disposed between the organic release layer 22 and the ultra-thin metal foil 3. It is used to prevent oxidation of the ultra-thin metal foil 3 after the carrier foil 1 is removed during lamination, which would affect its quality. It is understood that without the antioxidant layer 4, the side of the ultra-thin metal foil 3 closest to the carrier foil 1 is easily oxidized under conditions such as temperature, moisture, and corrosive gases, leading to abnormal circuit processing. Therefore, in this embodiment of the invention, the antioxidant layer 4 is disposed between the organic release layer 22 and the ultra-thin metal foil 3, which can prevent oxidation reactions between the ultra-thin metal foil 3 and the side of the ultra-thin metal foil 3 closest to the carrier foil 1 caused by temperature, moisture, corrosive gases, etc., thereby improving the quality and performance of the metal foil.

[0052] The present invention provides a method for preparing an ultrathin metal foil with a carrier, which has the following advantages: A metal release layer is prepared by electrodeposition on the surface of the carrier foil, and an organic release layer layer is formed by immersing an organic release layer solution on the surface of the metal release layer, thus preparing a composite release layer. This allows the metal release layer to form a strong interfacial bond with the carrier foil, while the organic release layer forms a weaker interfacial bond with the ultrathin metal foil, achieving differentiated control of interfacial strength and enabling the ultrathin metal foil to be released. Simultaneously, during the preparation process of the organic release layer, ultrasonic treatment is introduced. Ultrasonic waves induce high-frequency vibrations in the liquid, generating microscale turbulence, breaking the surface tension constraints of the solution, and spreading into a film. Ultrasonic waves generate periodic pressure changes in the liquid, forming tiny vacuum bubbles. These bubbles expand during negative pressure periods and collapse violently during positive pressure periods, generating local high pressure and high-speed microjets that scour the surface of the carrier foil, removing adsorbed bubbles and contaminants, and enhancing the uniformity of the release material's adhesion. At the same time, cavitation energy can break the oxide layer on the surface of the carrier foil, exposing fresh active sites and promoting the chemical bonding of the release layer molecules. This promotes the formation of the organic release layer, making the organic release layer form faster, the film layer thicker and more uniform, and the production efficiency higher. It can also improve the release stability and increase production efficiency.

[0053] To demonstrate the beneficial effects of the method for preparing an ultrathin metal foil with a carrier provided in the embodiments of the present invention, the following description is provided in conjunction with several embodiments and comparative examples.

[0054] Example 1:

[0055] An ultrathin copper foil with a carrier comprises a carrier foil, a metal release layer, an organic release layer, and an ultrathin copper foil stacked sequentially, and its preparation method includes the following steps:

[0056] 1) Polish the carrier copper foil, and then use acetone, anhydrous ethanol, and 10 vol.% dilute sulfuric acid to degrease and pickle the surface of the copper foil in sequence.

[0057] 2) Using the copper foil carrier treated in step 1) as the cathode and the ruthenium-iridium-titanium plate as the anode, the copper foil carrier is immersed in a nickel electrodeposition solution at 45°C for direct current electrodeposition to form a metal release layer. The electrodeposition current density is 5 A / dm³. 2 The electrolysis time was 75 seconds; the electrodeposition nickel solution system consisted of nickel sulfate hexahydrate with a concentration of 150 g / L, boric acid with a concentration of 40 g / L, and chloride with a concentration of 20 g / L.

[0058] 3) The carrier copper foil containing the metal release layer in step 2) is immersed in an adenine organic release layer solution with a concentration of 10 g / L for adsorption. Sulfuric acid with a concentration of 150 g / L is added to the organic release layer solution, and the temperature of the organic release layer solution is 20°C. Ultrasonic treatment is then performed with an ultrasonic frequency of 100 kHz, an ultrasonic power of 150 W, and an immersion time of 120 s to form an organic release layer, thus obtaining a composite release layer.

[0059] 4) The carrier copper foil containing the composite release layer from step 3) is immersed as the cathode in a copper plating solution at 25°C, and an iron-iridium-titanium plate is used as the anode to perform electrodeposition to form an extremely thin copper foil at a current density of 5 A / dm³. 2 The electrolysis time was 200s, the electrolyte temperature was 25℃, and the electroplating solution system contained copper with a concentration of 50g / L, sulfuric acid with a concentration of 80g / L, chloride with a concentration of 20ppm, hydroxyethyl cellulose with a concentration of 20ppm, and gelatin with a concentration of 40ppm.

[0060] Example 2:

[0061] The carrier-supported ultrathin metal foil in this embodiment is the same as that in Example 1, except that in step 3), the temperature of the organic stripping layer solution is 50°C.

[0062] Example 3:

[0063] The carrier-supported ultrathin metal foil in this embodiment is the same as that in Example 1, except that in step 3), the concentration of adenine in the organic stripping layer solution is 5 g / L.

[0064] Example 4:

[0065] The carrier-supported ultrathin metal foil in this embodiment is the same as that in Embodiment 1, except that in step 3), the ultrasonic power is 120W.

[0066] Example 5:

[0067] The carrier-supported ultrathin metal foil in this embodiment is the same as that in Embodiment 1, except that in step 3), the ultrasonic power is 90W.

[0068] Example 6:

[0069] The carrier-supported ultrathin metal foil in this embodiment is the same as that in Embodiment 1, except that in step 3), the ultrasonic power is 30W.

[0070] Example 7:

[0071] The carrier-supported ultrathin metal foil in this embodiment is the same as that in Embodiment 1, except that in step 3), the ultrasonic frequency is 80kHz.

[0072] Example 8:

[0073] The carrier-supported ultrathin metal foil in this embodiment is the same as that in Embodiment 1, except that in step 3), the ultrasonic frequency is 20kHz.

[0074] Comparative Example 1:

[0075] An ultrathin copper foil with a carrier comprises a carrier foil, a metal release layer, and an ultrathin copper foil stacked sequentially, and its preparation method includes the following steps:

[0076] 1) Polish the carrier copper foil, and then use acetone, anhydrous ethanol, and 10 vol.% dilute sulfuric acid to degrease and pickle the surface of the copper foil in sequence.

[0077] 2) Using the copper foil carrier treated in step 1) as the cathode and the ruthenium-iridium-titanium plate as the anode, the copper foil carrier is immersed in a nickel electrodeposition solution at 45°C for direct current electrodeposition to form a metal release layer. The electrodeposition current density is 5 A / dm³. 2 The electrolysis time was 75 seconds; the electrodeposition nickel solution system consisted of nickel sulfate hexahydrate with a concentration of 150 g / L, boric acid with a concentration of 40 g / L, and chloride with a concentration of 20 g / L.

[0078] 3) The carrier copper foil containing the metal stripping layer from step 2) is immersed as the cathode in a copper plating solution at 25°C, and a ruthenium-iridium-titanium plate is used as the anode to perform electrodeposition to form an extremely thin copper foil at a current density of 5 A / dm³. 2 The electrolysis time was 200s, the electrolyte temperature was 25℃, and the electroplating solution system contained copper with a concentration of 50g / L, sulfuric acid with a concentration of 80g / L, chloride with a concentration of 20ppm, hydroxyethyl cellulose with a concentration of 20ppm, and gelatin with a concentration of 40ppm.

[0079] Comparative Example 2:

[0080] An ultrathin copper foil with a carrier comprises a carrier foil, a metal release layer, an organic release layer, and an ultrathin copper foil stacked sequentially, and its preparation method includes the following steps:

[0081] 1) Polish the carrier copper foil, and then use acetone, anhydrous ethanol, and 10 vol.% dilute sulfuric acid to degrease and pickle the surface of the copper foil in sequence.

[0082] 2) Using the copper foil carrier treated in step 1) as the cathode and the ruthenium-iridium-titanium plate as the anode, the copper foil carrier is immersed in a nickel electrodeposition solution at 45°C for direct current electrodeposition to form a metal release layer. The electrodeposition current density is 5 A / dm³. 2 The electrolysis time was 75 seconds; the electrodeposition nickel solution system consisted of nickel sulfate hexahydrate with a concentration of 150 g / L, boric acid with a concentration of 40 g / L, and chloride with a concentration of 20 g / L.

[0083] 3) The carrier copper foil containing the metal stripping layer in step 2) is immersed in an adenine organic stripping layer solution with a concentration of 10 g / L for adsorption. Sulfuric acid with a concentration of 150 g / L is added to the organic stripping layer solution. The temperature of the organic stripping layer solution is 20°C, thereby forming an organic stripping layer and obtaining a composite stripping layer.

[0084] 4) The carrier copper foil containing the composite release layer from step 3) is immersed as the cathode in a copper plating solution at 25°C, and an iron-iridium-titanium plate is used as the anode to perform electrodeposition to form an extremely thin copper foil at a current density of 5 A / dm³. 2 The electrolysis time was 200s, the electrolyte temperature was 25℃, and the electroplating solution system contained copper with a concentration of 50g / L, sulfuric acid with a concentration of 80g / L, chloride with a concentration of 20ppm, hydroxyethyl cellulose with a concentration of 20ppm, and gelatin with a concentration of 40ppm.

[0085] Peel strength tests and peel strength uniformity calculations were performed on the carrier-supported ultrathin metal foils of Examples 1-8 and Comparative Examples 1-2. The carrier-supported ultrathin metal foils to be tested were pressed onto a base film (25 μm TPI film) (pressure transmission, heat preservation section: pressing temperature 220℃ * time 2 hours * pressure 25 kg). Test strips were cut using a strip cutter. Ten test strips were cut from each set of examples, with a width of 15 mm and a length of 150 mm. The tensile rate was 50 mm / min. The peel strength between the ultrathin metal foil and the carrier foil was tested, and the average value was taken. (maximum value - average value) / average value was used as the upper limit of the rate of change, and (minimum value - average value) / average value was used as the lower limit of the rate of change. The test data are shown in Table 1.

[0086] Table 1. Average peel strength and uniformity of peel strength of carrier-supported ultrathin metal foils in Examples 1-8 and Comparative Examples 1-2.

[0087]

[0088] As shown in Table 1, by using the carrier-supported ultrathin metal foil and its preparation method of the present invention, a composite release layer is formed, achieving stable release. This solves the problem of uneven organic release layer and low efficiency in the current process of preparing carrier-supported ultrathin copper foil, thereby ensuring the release stability of the organic release layer and improving production efficiency.

[0089] In summary, the carrier-supported ultrathin metal foil comprises a carrier foil, a metal release layer, an organic release layer, and an ultrathin metal foil stacked sequentially. The metal release layer is prepared by electrodeposition on the surface-treated carrier foil, and an organic release layer solution is dipped into the surface of the metal release layer to form an organic release layer, thus creating a composite release layer. This results in a strong interfacial bond between the metal release layer and the carrier foil, and a weaker interfacial bond between the organic release layer and the ultrathin metal foil, achieving differentiated control of interfacial strength and enabling the ultrathin metal foil to be peeled off. Simultaneously, ultrasonic treatment is introduced during the preparation of the organic release layer to promote its formation, resulting in faster formation, a thicker and more uniform film, higher production efficiency, improved peeling stability, and increased production efficiency.

[0090] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0091] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for producing a carrier-backed extremely thin metal foil, characterized by, The carrier foil of the strip includes a carrier foil, a metal stripping layer, an organic stripping layer and an ultra-thin metal foil which are sequentially stacked, and the preparation method of the carrier foil of the strip includes the following steps: 1) forming a metal stripping layer on the surface of the carrier foil by electrodeposition, wherein the metal stripping layer includes at least one element selected from chromium, nickel, cobalt, iron, copper and titanium; 2) immersing the carrier foil including the metal stripping layer into an organic stripping layer solution for ultrasonic treatment to form an organic stripping layer, wherein the organic stripping layer includes at least one substance selected from adenine, guanine, xanthine, hypoxanthine, caffeine and theophylline; 3) forming an ultra-thin metal foil on the surface of the organic stripping layer.

2. The method of claim 1, wherein the carrier-supported extremely thin metal foil is prepared by the steps of: In step 1), at least one side of the carrier foil is subjected to surface treatment before the electrodeposition of the metal stripping layer, and the surface treatment includes at least one of polishing, removing the oxide layer and removing the oil stain. ​ 3. The method of claim 2, wherein the carrier is removed by etching. The surface treatment of the carrier foil is sequentially performed by using acetone, anhydrous ethanol and 10 vol.% dilute sulfuric acid.

4. The method for preparing an ultrathin metal foil with a carrier as described in claim 1, characterized in that, In step 1), the metal stripping layer is metal nickel.

5. The method of claim 4, wherein the carrier is removed by etching. The electrolyte for electrodeposition of the metal nickel comprises 50-300 g / L of nickel sulfate hexahydrate, 20-120 g / L of boric acid, and 20-120 g / L of chloride; the electrolyte temperature is 20-70℃, the current density is 5-30 A / dm 2 , and the electrolysis time is 10-200 s.

6. The method for preparing an ultrathin metal foil with a carrier as described in claim 1, characterized in that, The concentration of the organic stripping layer is 0.1 g / L-10 g / L.

7. The method for preparing an ultrathin metal foil with a carrier as described in claim 1, characterized in that, In step 2), the ultrasonic frequency is 10-150 kHz, the ultrasonic power is 10-150 W, and the immersion coating time is 10-3000 s.

8. The method for preparing an ultrathin metal foil with a carrier as described in claim 1, characterized in that, In step 2), the carrier foil including the metal stripping layer is 2-20 cm away from the bottom of the organic stripping layer solution.

9. The method of producing a supported ultrathin metal foil according to any one of claims 1 to 8, wherein The extremely thin metal foil in step 3) is an extremely thin copper foil formed by electrodeposition using an electrolyte with a copper concentration of 50-110 g / L, a sulfuric acid concentration of 80-120 g / L, a chloride concentration of 20-50 ppm, a hydroxyethyl cellulose concentration of ≤20 ppm, and a gelatin concentration of ≤40 ppm; an electrolyte temperature of 20-70 °C, a current density of 5-30 A / dm 2 , and an electrolysis time of 10-200 s.

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