Carrier metal foil and metal-coated laminate

Abstract

This invention discloses a carrier-supported metal foil and a metal-clad laminate. The release layer comprises an alloy layer, a transition layer, and an organic layer stacked sequentially. The alloy layer is disposed on one side of the carrier layer, the organic layer on one side of the functional layer, and the transition layer is disposed between the alloy layer and the organic layer. This invention employs a metal-organic composite gradient release layer. During high-temperature pressing, the significant difference in properties between the organic layer and the functional layer results in slow atomic diffusion, thus ensuring the stability of the release force of the carrier-supported metal foil. Simultaneously, the metal-organic composite gradient release layer can gradually release the release stress, disperse the interfacial shear force, avoid sudden stress changes during release, ensure the flatness of the functional layer surface, and prevent tearing and other defects, thereby improving quality reliability and processing efficiency.

Description

Technical Field

[0001] This invention relates to the field of electronic information materials technology, and in particular to a carrier metal foil and a metal-coated laminate. Background Technology

[0002] With the rapid development of the 5G industry, the PCB industry is booming as a result. From the perspective of downstream PCB applications, communications, mobile phones, servers, data storage, and automobiles will become the best sub-sectors for PCBs in the next five years, and the demand for high-end PCB products such as multilayer boards, HDI, flexible boards, and IC packaging substrates will increase significantly. At the same time, from the perspective of the upstream industry chain, copper foil, as an indispensable part of the industry chain, is a key material for high-frequency and high-speed printed circuit boards for 5G communications. Copper foil plays an important role in both the raw material copper-clad laminate and the PCB manufacturing process.

[0003] In recent years, as consumer electronics such as smartphones and wearable devices have continued to become smaller and thinner, there is a need to integrate more functions within a limited space, prompting PCBs to adopt ultra-fine lines to improve integration. The rapid development of fields such as artificial intelligence, 5G communication, and high-performance computing has placed higher demands on PCBs in devices such as AI servers and 5G base stations, requiring ultra-fine lines to achieve higher signal transmission speeds and lower latency.

[0004] Ultra-thin copper foil represents the future development direction and a hot market demand for copper foil. Currently, the thickness of copper foil is gradually moving towards 12μm, 9μm, 5μm, and even thinner. However, due to the low mechanical strength of ultra-thin copper foil, it is difficult to achieve complete peeling from the cathode roller during its preparation, and it is prone to curling, wrinkling, or tearing during transportation, thus affecting subsequent applications. Therefore, Japanese companies have abandoned conventional copper foil manufacturing methods and creatively proposed a technology for preparing ultra-thin carrier copper foil. The carrier provides support, solving the problems of transportation and storage.

[0005] Peelable copper foil with a carrier is widely used for lamination with a substrate via hot pressing, followed by peeling off the carrier layer, leaving a thin copper layer as a copper-clad laminate. However, in current peelable copper foils, the release layer is often made of a single metal or alloy metal. Since the thin copper layer is also a single metal with similar properties, the high temperature during hot pressing accelerates the atomic diffusion rate between the release layer and the thin copper layer, increasing the peeling force and resulting in poor stability. This makes it prone to poor peeling when removing the carrier layer, leading to tearing and damage on the peeled thin copper side, which affects subsequent circuit fabrication.

[0006] To address the issue of stable peel force between the carrier layer and the functional layer, it is urgent to develop a carrier-coated copper foil with stable peel force. Summary of the Invention

[0007] The purpose of this invention is to provide a laminated metal foil and metal-coated layer with a carrier. By optimizing the structure of the release layer, the problem of poor stability of the release force under high temperature pressing is solved, the stability during release is improved, and adverse problems such as peeling, tearing and breakage of the thin copper layer are avoided.

[0008] To achieve the above objectives, a first aspect of the present invention provides a carrier-supported metal foil, comprising: a carrier layer, a release layer, and a functional layer stacked sequentially;

[0009] The release layer comprises an alloy layer, a transition layer, and an organic layer; the alloy layer is disposed on one side of the carrier layer, the organic layer is disposed on one side of the functional layer, and the transition layer is disposed between the alloy layer and the organic layer.

[0010] In one embodiment, the alloy layer is a nickel-chromium alloy layer or a carbon-doped alloy layer.

[0011] In one embodiment, when the alloy layer is a nickel-chromium alloy layer, the mass fraction ratio of nickel to chromium is 4:1.

[0012] In one embodiment, the transition layer comprises alloying elements in the alloy layer and organic matter in the organic layer.

[0013] In one embodiment, the alloying elements in the transition layer and the organic matter are chemically bonded to form a transition layer through plasma treatment.

[0014] In one embodiment, the organic layer comprises polyimide or modified epoxy resin.

[0015] In one embodiment, the thicknesses of the alloy layer, transition layer, and organic layer in the release layer increase in an increasing manner, wherein the thickness of the alloy layer is 0.1 μm to 0.5 μm, the thickness of the transition layer is 0.3 μm to 0.7 μm, and the thickness of the organic layer is 0.5 μm to 1 μm.

[0016] In one embodiment, the peeling force between the alloy layer and the carrier layer in the release layer is denoted as F1, and the peeling force between the organic layer and the functional layer is denoted as F2, where F1 > 1.5F2.

[0017] In one embodiment, the roughness Rz of the organic layer on the side closest to the functional layer is ≤0.5μm.

[0018] To achieve the above objectives, a second aspect of the present invention also provides a metal-clad laminate, the metal-clad laminate comprising the carrier metal foil described in any of the above embodiments.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows: the release layer includes an alloy layer, a transition layer, and an organic layer, and adopts a metal-organic composite gradient release layer. The alloy layer is disposed on one side of the carrier layer, the organic layer is disposed on one side of the functional layer, and the transition layer is disposed between the alloy layer and the organic layer. Through the ingenious design of the composition gradient, a smooth transition of the release force is achieved. During high-temperature pressing, since the alloy layer is close to the carrier layer and the organic layer is close to the functional layer, the properties of the organic layer and the functional layer are significantly different, and atomic diffusion is slow. This ensures the stability of the release force between the organic layer and the functional layer, making the release process more thorough, ensuring the flatness of the functional layer surface, and preventing adverse phenomena such as tearing and breakage.

[0020] On the other hand, the release layer adopts a metal-organic composite gradient release layer, which releases the release stress step by step and disperses the interfacial shear force, thus achieving a smooth transition of the release force. It avoids stress abrupt changes during release, ensures the flatness of the functional layer surface, and prevents adverse phenomena such as tearing and breakage. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the first type of carrier-supported metal foil provided in the embodiments of the present invention;

[0022] Figure 2 This is a schematic diagram of the second type of carrier metal foil provided in the embodiments of the present invention.

[0023] The structure consists of: 1. Carrier layer; 2. Release layer; 21. Alloy layer; 22. Transition layer; 23. Organic layer; 3. Functional layer; and 4. Antioxidant layer. Detailed Implementation

[0024] 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.

[0025] 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.

[0026] 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.

[0027] Please see Figure 1 , Figure 1 This is a schematic diagram of a carrier-supported metal foil according to an embodiment of the present invention. The embodiment of the present invention provides a carrier-supported metal foil comprising a carrier layer 1, a release layer 2, and a functional layer 3 stacked sequentially; wherein, the release layer 2 comprises an alloy layer 21, a transition layer 22, and an organic layer 23; the alloy layer 21 is disposed on one side of the carrier layer 1, the organic layer 23 is disposed on one side of the functional layer 3, and the transition layer 22 is disposed between the alloy layer 21 and the organic layer 23.

[0028] It is worth noting that in practical applications, such as in the field of circuit boards, the functional layer 3 of the carrier metal foil is high-temperature laminated to the substrate of the circuit board, and then the carrier layer 1 is peeled off, leaving the functional layer on the substrate. The desired circuit is then formed through circuit board processing. Alternatively, the carrier layer 1 of the carrier metal foil is high-temperature laminated to the substrate of the circuit board, the desired circuit is formed through circuit board processing, and finally the carrier layer 1 and functional layer 3 are peeled off. For example, in the field of electronic materials production, the functional layer 3 of the carrier metal foil is high-temperature laminated onto a base film to produce a metal-clad laminate. Alternatively, the carrier layer 1 of the carrier metal foil can be high-temperature laminated onto a base film to produce a flexible metal-clad laminate.

[0029] In this embodiment of the invention, the release layer 2 is a metal-organic composite gradient release layer. The alloy layer is disposed on one side of the carrier layer 1, the organic layer on one side of the functional layer 3, and the transition layer 22 is disposed between the alloy layer 21 and the organic layer 23. Through the ingenious design of the composition gradient, a smooth transition of the release force is achieved. During high-temperature pressing, because the alloy layer 21 is close to the carrier layer 1 and the organic layer 23 is close to the functional layer 3, the properties of the organic layer 23 and the functional layer 3 differ significantly, resulting in slow atomic diffusion. This ensures the stability of the release force between the organic layer 23 and the functional layer 3, making the release process more thorough, ensuring the smoothness of the functional layer 3 surface, and preventing tearing and other adverse phenomena. Simultaneously, the metal-organic composite gradient release layer 2 releases the release stress step by step, dispersing the interfacial shear force and achieving a smooth transition of the release force. This avoids sudden stress changes during release, ensuring the smoothness of the functional layer 3 surface and preventing tearing and other adverse phenomena.

[0030] Furthermore, in this embodiment of the invention, the alloy layer 21 is a nickel-chromium alloy layer or a carbon-doped alloy layer. Nickel-chromium alloys, as a release layer, possess good thermal stability, maintaining their physical properties over a wide temperature range without softening or deformation due to temperature increases. This ensures the release layer can function effectively and continuously. Additionally, nickel-chromium alloys have high hardness, allowing them to withstand significant frictional forces without wear, reducing the problem of decreased release performance due to wear. Meanwhile, carbon-doped alloys, as a release layer, are suitable for high-temperature release processes due to the extremely high melting point of carbides, and possess excellent resistance to chemical corrosion, preventing damage to the release layer in harsh environments that could hinder release.

[0031] Preferably, in this embodiment of the invention, when the alloy layer 21 is a nickel-chromium alloy, the mass fraction ratio of nickel to chromium is 4:1. By limiting the mass fraction ratio of nickel to chromium to 4:1, the plasticity of nickel and the strengthening effect of chromium are combined, ensuring the thermal stability of the release layer 2 during high-temperature pressing. When the chromium content is 20%, a Cr2O3 oxide film can be formed, enhancing the chemical bonding effect. When the nickel content is 80%, its ductility can reduce interfacial thermal stress and prevent the release strength from rapidly decreasing at high temperatures, leading to delamination. Therefore, limiting the mass fraction ratio of nickel to chromium to 4:1, under this design ratio, the coefficient of thermal expansion of the nickel-chromium alloy is close to that of the functional layer 3 and the organic layer 23, reducing interfacial stress under thermal cycling and preventing cracking or debonding of the release layer 2 from the carrier layer 1 or the functional layer 3. Combining the chemical bonding effect of chromium and the ductility of nickel, the thermal stability of the release layer during high-temperature pressing can be effectively guaranteed, avoiding defects such as delamination.

[0032] Furthermore, in this embodiment of the invention, the transition layer 22 includes the alloying elements in the alloy layer 21 and the organic matter in the organic layer 23. By designing the transition layer 22 to include the alloying elements in the alloy layer 21 and the organic matter in the organic layer 23, on the one hand, because the transition layer 22 contains both the same elements as the alloy layer 21 and the same substances as the organic matter 23, the thermal stress at the interface of the multilayer structure of the release layer 2 is reduced, preventing a rapid decrease in peel strength at high temperatures, which could lead to delamination between the release layer 2 and the carrier layer 1 or the functional layer 3, thereby ensuring stable peeling of the copper foil with the carrier. On the other hand, because the transition layer 22 contains both the same elements as the alloy layer 21 and the same substances as the organic matter 23, the transition layer 22 has good adhesion to both the alloy layer 21 and the organic layer 23, preventing delamination of the release layer 2 itself, which could leave organic matter 23 residue on the surface of the functional layer 3, thus affecting the subsequent use of the functional layer 3. For example, if organic matter 23 remains on the surface of the functional layer 3, it would be difficult to etch circuits into the functional layer 3 during IC substrate processing, rendering it unusable.

[0033] Preferably, in this embodiment of the invention, the alloying elements in the transition layer 22 form chemical bonds with the organic matter through plasma treatment. High-energy particles (such as O2, N2, Ar⁺, etc.) in the plasma bombard the material surface, breaking existing chemical bonds and generating active free radicals. These active sites can react chemically with subsequently coated or deposited materials to form chemical bonds. Furthermore, by selecting different plasma gases, specific functional groups can be introduced onto the material surface, enhancing chemical bonding with other substances. Plasma treatment for chemical bonding is a physical method to increase bonding between material interfaces; it is environmentally friendly, pollution-free, and highly efficient. The degree of chemical bonding is controllable, ensuring stable and reliable chemical bonding between the alloying elements and organic matter in the transition layer 22, thereby improving the stability of the release layer 2.

[0034] Furthermore, in this embodiment of the invention, the organic layer 23 comprises polyimide or modified epoxy resin. Using polyimide or modified epoxy resin results in lower surface energy and lower viscosity, which can reduce peeling resistance by 50% to 90%, improve efficiency, and avoid difficulties in peeling; simultaneously, it avoids residue after peeling, which could affect subsequent processes, thereby improving yield.

[0035] Furthermore, in this embodiment of the invention, the roughness Rz of the organic layer 23 near the functional layer 3 is ≤0.5μm. By limiting the roughness Rz of the organic layer 23 near the functional layer 3 to ≤0.5μm, the surface profile of the functional layer 3 near the release layer 2 is extremely low after peeling, resulting in a circuit with less signal loss, suitable for high-frequency and high-speed signal transmission requirements. Specifically, the surface of the carrier layer 1 near the release layer 2 is rough, and the surfaces of the alloy layer 21 and transition layer 22 formed on the carrier layer 1 are also rough. By setting the organic layer 23 to fill the rough surface of the transition layer 22, the roughness of the organic layer 23 near the functional layer 3 is lower, resulting in a lower surface roughness of the functional layer 3 near the release layer 2, forming a circuit with an extremely low profile, resulting in less signal loss, suitable for high-frequency and high-speed signal transmission requirements.

[0036] Preferably, in the embodiments of the present invention, the thicknesses of the alloy layer 21, the transition layer 22 and the organic layer 23 tend to increase, wherein the thickness of the alloy layer 21 is 0.1 μm to 0.5 μm, the thickness of the transition layer 22 is 0.3 μm to 0.7 μm, and the thickness of the organic layer 23 is 0.5 μm to 1 μm.

[0037] For example, in this embodiment of the invention, the structure of the release layer 2 is that the alloy layer 21 is NiCr, the organic layer 23 is PI, and the transition layer 22 is a chemically bonded transition layer NiCr-PI mixed layer formed by plasma treatment. Through the ingenious design of the gradient of the release layer 2 (NiCr→NiCr-PI mixed layer→PI), a smooth transition of the release force is achieved. During the high-temperature pressing process, since the alloy layer 21 is closer to the carrier layer 1, the release strength is greater; while the organic layer 23 is closer to the functional layer 3, and the two have significant differences in properties, resulting in slow atomic diffusion. This allows the carrier layer 1, together with the release layer 2, to be completely separated from the functional layer 3, making the release process more thorough and ensuring the stability of the release force between the organic layer 23 and the functional layer 3.

[0038] It is worth noting that, in this embodiment of the invention, the release layer 2 is processed onto the carrier layer 1 by physical vapor deposition and / or electrolysis. Exemplarily, the electrolysis method involves first electroplating alloy layers of different proportions sequentially onto the surface of the carrier layer 1 near the release layer 2, and then coating the alloy layers with a low-adhesion polymer by spraying or spin coating. Physical vapor deposition uses vacuum equipment, adjusts the target material composition, and deposits a gradient composite release layer.

[0039] Preferably, in this embodiment of the invention, physical vapor deposition is performed using magnetron sputtering. The resulting release layer 2 has high purity and good uniformity, producing a high-quality release layer with uniform thickness and composition, free of impurities, suitable for release layers with nanometer-level thickness. Simultaneously, physical vapor deposition forms a strong release layer 2 on the carrier layer 1, which helps improve the peel strength between the carrier layer 1 and the release layer 2, making it less prone to detachment or peeling. The release layer 2 prepared using physical vapor deposition has high purity, good uniformity, and excellent adhesion. It is also pollution-free, has a moderate operating temperature, high efficiency, and offers high controllability over the composition, structure, and thickness of the release layer 2, facilitating adjustment and optimization of its performance.

[0040] Furthermore, in this embodiment of the invention, the peel force between the alloy layer 21 and the carrier layer 1 is denoted as F1, and the peel force between the organic layer 23 and the functional layer 3 is denoted as F2, where F1 > 1.5 F2. By limiting the peel force between the alloy layer 21 and the carrier layer 1, and the peel force between the organic layer 23 and the functional layer 3, the reliability of peeling off the carrier metal foil can be guaranteed. Because F1≤1.5F2, during peeling, the alloy layer 21 will not separate from the carrier layer 1, resulting in the organic layer 23 remaining on the surface of the functional layer 3, affecting the subsequent use of the functional layer 3. For example, if the organic layer 23 remains on the surface of the functional layer 3, it will be difficult to etch the circuits during IC substrate processing, rendering the functional layer 3 unusable. Therefore, the peeling force between the alloy layer 21 side and the carrier layer 1 is denoted as F1, and the peeling force between the organic layer 23 side and the functional layer 3 is denoted as F2, where F1>1.5F2. During peeling, it can be ensured that the carrier layer 1 is peeled off together with the peeling layer 2, without any peeling layer 2 residue, making the peeling process more thorough, thereby ensuring the stability of the peeling force between the organic layer 23 and the functional layer 3.

[0041] It should be noted that, in this embodiment of the invention, the extremely thin functional layer 3 is too thin to be directly processed and cannot be used directly in application. Therefore, a carrier layer 1 is required, which serves a supporting function to support the functional layer 3. The thickness of the carrier layer 1 is 8~28μm. The material of the carrier layer 1 can be at least one of aluminum, titanium, zinc, iron, nickel, chromium, cobalt, copper, silver, and gold.

[0042] In this embodiment of the invention, functional layer 3 is used to fabricate circuitry. The thickness of functional layer 3 is 1~5μm. The material of functional layer 3 can be at least one of aluminum, titanium, zinc, iron, nickel, chromium, cobalt, copper, silver, and gold.

[0043] See Figure 2 , Figure 2This invention provides another type of carrier-supported metal foil. In this embodiment, the carrier-supported metal foil further includes an antioxidant layer 4, which is disposed between the organic layer 23 and the functional layer 3. This antioxidant layer 4 is used to prevent oxidation of the functional layer 3 after the carrier layer 1 is removed during lamination, thus preventing quality issues. It is understood that without the antioxidant layer 4, the side of the functional layer 3 closest to the carrier layer 1 is easily oxidized under conditions such as temperature, moisture, and corrosive gases, leading to abnormal circuit processing. Therefore, in this embodiment, the antioxidant layer 4 is disposed between the organic layer 23 and the functional layer 3, which can prevent oxidation reactions between the functional layer 3 and the side close to the carrier layer 1 caused by temperature, moisture, and corrosive gases, thereby improving the quality and performance of the metal foil.

[0044] Embodiments of the present invention also provide a metal-clad laminate, which includes a carrier metal foil according to any embodiment of the present invention.

[0045] It is worth noting that, in this embodiment of the invention, the functional layer 3 with the carrier metal foil is high-temperature pressed onto the base film to fabricate a flexible metal-clad laminate. Alternatively, the carrier layer 1 with the carrier metal foil can be high-temperature pressed onto the base film to fabricate a flexible metal-clad laminate.

[0046] The beneficial effects of the carrier-supported metal foil and metal-clad laminate provided in this embodiment of the invention are as follows: the release layer 2 includes an alloy layer 21, a transition layer 22, and an organic layer 23. It adopts a metal-organic composite gradient release layer. The alloy layer 21 is disposed on one side of the carrier layer 1, the organic layer 23 is disposed on one side of the functional layer 3, and the transition layer 22 is disposed between the alloy layer 21 and the organic layer 23. Through the ingenious design of the composition gradient, a smooth transition of the release force is achieved. During high-temperature pressing, since the alloy layer 21 is close to the carrier layer 1 and the organic layer 23 is close to the functional layer 3, the organic layer 23 and the functional layer 3 have significantly different properties and slow atomic diffusion, thereby ensuring the stability of the release force between the organic layer 23 and the functional layer 3, making the release process more thorough, ensuring the flatness of the surface of the functional layer 3, and preventing adverse phenomena such as tearing and breakage.

[0047] On the other hand, the peeling layer 2 adopts a metal-organic composite gradient peeling layer, which releases peeling stress step by step and disperses interfacial shear force, thus achieving a smooth transition of peeling force. It avoids stress abrupt changes during peeling, ensures the flatness of the surface of the functional layer 3, and prevents adverse phenomena such as tearing and breakage.

[0048] To demonstrate the beneficial effects of the carrier-supported metal foil and metal-coated laminate provided in the embodiments of the present invention, the following description is provided in conjunction with several embodiments and comparative examples.

[0049] Example 1:

[0050] A carrier-supported metal foil includes a carrier layer, a release layer, and a functional layer stacked sequentially. The release layer comprises an alloy layer, a transition layer, and an organic layer. The alloy layer is disposed on one side of the carrier layer, the organic layer is disposed on one side of the functional layer, and the transition layer is disposed between the alloy layer and the organic layer. The alloy layer is a nickel-chromium alloy with a nickel-to-chromium mass fraction ratio of 7:1 and a thickness of 0.6 μm. The organic layer is polyimide with a thickness of 0.4 μm, and the transition layer has a thickness of 0.2 μm.

[0051] Example 2:

[0052] The carrier metal foil in this embodiment is the same as that in Embodiment 1, except that the mass fraction ratio of nickel to chromium in the nickel-chromium alloy layer is 4:1.

[0053] Example 3:

[0054] The carrier metal foil in this embodiment is the same as that in Embodiment 1, except that the transition layer includes alloying elements in the alloy layer and organic matter in the organic layer.

[0055] Example 4:

[0056] The carrier-supported metal foil in this embodiment is the same as that in Embodiment 1, except that: a carrier-supported metal foil is provided, wherein the transition layer comprises alloying elements in the alloy layer and organic matter in the organic layer. The thicknesses of the alloy layer, transition layer, and organic layer increase in an increasing trend, wherein the thickness of the alloy layer is 0.2 μm, the thickness of the transition layer is 0.5 μm, and the thickness of the organic layer is 1 μm.

[0057] Example 5:

[0058] The carrier-supported metal foil in this embodiment is the same as that in Embodiment 1, except that: a carrier-supported metal foil is provided, wherein the mass fraction ratio of nickel to chromium in the nickel-chromium alloy layer is 4:1, and the transition layer includes alloying elements from the alloy layer and organic matter from the organic layer. The thicknesses of the alloy layer, transition layer, and organic layer increase in an increasing trend, wherein the thickness of the alloy layer is 0.2 μm, the thickness of the transition layer is 0.5 μm, and the thickness of the organic layer is 1 μm. The peel force F1 between the alloy layer and the carrier layer and the peel force F2 between the organic layer and the functional layer satisfy F1 > 1.5F2.

[0059] Example 6:

[0060] The carrier-supported metal foil in this embodiment is the same as that in Embodiment 1, except that: a carrier-supported metal foil is used, wherein the mass fraction ratio of nickel to chromium in the nickel-chromium alloy layer is 4:1, and the transition layer includes alloying elements from the alloy layer and organic matter from the organic layer. The thicknesses of the alloy layer, transition layer, and organic layer increase in an increasing trend, wherein the thickness of the alloy layer is 0.2 μm, the thickness of the transition layer is 0.5 μm, and the thickness of the organic layer is 1 μm, and the roughness Rz of the organic layer near the functional layer is ≤0.5 μm.

[0061] Comparative Example 1:

[0062] A carrier-supported metal foil includes a carrier layer, a release layer, and a functional layer stacked sequentially; wherein the release layer is a Ni-Mo alloy layer.

[0063] Comparative Example 2:

[0064] A carrier-supported metal foil comprises a carrier layer, a release layer, and a functional layer stacked sequentially; wherein the release layer is an organic compound of benzotriazole (BTA).

[0065] Comparative Example 3:

[0066] A carrier-supported metal foil includes a carrier layer, a release layer, and a functional layer stacked sequentially; wherein the release layer is a 2-benzimidazole thiol (BIT) organic compound and a nickel plating layer stacked sequentially.

[0067] Peel strength tests were performed on the carrier-supported metal foils of Examples 1-6 and Comparative Examples 1-3. The carrier-supported metal foils to be tested were pressed onto the base film (25 μm TPI film) (pressure transmission, heat preservation section: pressing temperature 220℃ * time 2 hours * pressure 25 kg), and then the peel between the functional layer and the carrier layer was evaluated. The test results are shown in Table 1.

[0068] Table 1. Peeling of carrier-supported metal foils in Examples 1-6 and Comparative Examples 1-3

[0069]

[0070] As shown in Table 1, by applying the carrier-supported metal foil described in this embodiment, the peeling condition between the carrier layer and the functional layer is excellent under high-temperature pressing conditions, which can ensure the peeling force stability of the carrier-supported metal foil, thereby improving quality reliability and processing efficiency.

[0071] In summary, the release layer of the carrier-supported metal foil employs a metal-organic composite gradient release layer, comprising an alloy layer, a transition layer, and an organic layer stacked sequentially. The alloy layer is disposed on one side of the carrier layer, the organic layer on one side of the functional layer, and the transition layer between the alloy layer and the organic layer. Through the ingenious design of the composition gradient, a smooth transition of the release force is achieved. On the one hand, during high-temperature pressing, because the alloy layer is close to the carrier layer and the organic layer is close to the functional layer, the significant difference in properties between the organic layer and the functional layer results in slow atomic diffusion, thus ensuring the stability of the release force of the carrier-supported metal foil, making the release process more thorough, ensuring the flatness of the functional layer surface, and preventing defects such as tearing and breakage. On the other hand, the metal-organic composite gradient release layer releases the release stress in stages, disperses the interfacial shear force, avoids stress abrupt changes during release, ensures the flatness of the functional layer surface, and prevents defects such as tearing and breakage; thereby improving quality reliability and processing efficiency. This invention solves the problem in the prior art that the peeling force between the carrier layer and the functional layer is difficult to control under high temperature pressing, resulting in unstable peeling and affecting processing efficiency.

[0072] 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.

[0073] The embodiments described above are merely illustrative of several implementation methods of this application, intended to facilitate a detailed understanding of the technical solutions of this application, but should not be construed as limiting the scope of protection 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 scope of protection of this application. It should be understood that technical solutions obtained by those skilled in the art based on the technical solutions provided in this application through logical analysis, reasoning, or limited experimentation are all within the scope of protection of the appended claims. Therefore, the scope of protection of this patent application should be determined by the content of the appended claims, and the specification can be used to interpret the content of the claims.

Claims

1. A carrier-supported metal foil, characterized in that, It includes a carrier layer, a release layer, and a functional layer stacked in sequence; the release layer is composed of an alloy layer, a transition layer, and an organic layer; the alloy layer is disposed on one side of the carrier layer and in contact with the carrier layer, the organic layer is disposed on one side of the functional layer and in contact with the functional layer, and the transition layer is disposed between the alloy layer, the carrier layer, and the organic layer; The alloy layer is a nickel-chromium alloy layer with a mass fraction ratio of nickel to chromium of 4:

1. The organic layer includes polyimide resin. The transition layer includes the alloying elements in the alloy layer and the organic matter in the organic layer. The carrier layer is at least one of aluminum, titanium, zinc, iron, nickel, chromium, cobalt, copper, silver, and gold. The functional layer is at least one of aluminum, titanium, zinc, iron, nickel, chromium, cobalt, copper, silver, and gold.

2. The carrier-supported metal foil according to claim 1, characterized in that, The alloying elements and organic matter in the transition layer are chemically bonded to form a transition layer through plasma treatment.

3. The carrier-supported metal foil according to claim 1, characterized in that, In the release layer, the thickness of the alloy layer, the transition layer, and the organic layer increases in an increasing trend, wherein the thickness of the alloy layer is 0.1μm~0.5μm, the thickness of the transition layer is 0.3μm~0.7μm, and the thickness of the organic layer is 0.5μm~1μm.

4. The carrier-supported metal foil according to claim 1, characterized in that, In the release layer, the peeling force between the alloy layer and the carrier layer is denoted as F1, and the peeling force between the organic layer and the functional layer is denoted as F2, where F1 > 1.5 F2.

5. The carrier-supported metal foil according to claim 1, characterized in that, The roughness Rz of the organic layer on the side closest to the functional layer is ≤0.5μm.

6. A metal-clad laminate, characterized in that, The metal-clad laminate comprises a carrier metal foil as described in any one of claims 1-5.

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