Metal foil, circuit board, copper-clad laminate, negative electrode material for battery, and battery

Abstract

Disclosed in the present application are a metal foil, a circuit board, a copper-clad laminate, a negative electrode material for a battery, and a battery. The metal foil comprises a first surface and an opposing second surface; a plurality of protrusions are present on the second surface, the maximum vertical height of the protrusions is 0.2-3 μm, and the average grain size of metal grains in the protrusions is 0.05-1.5 μm. With respect to the metal foil, circuit board, copper-clad laminate, negative electrode material for a battery, and battery of the present application, by means of the design of the protrusions and the average grain size on the metal foil, the metal foil is made to have good corrosion resistance, side corrosion of a circuit can be mitigated, product yield is effectively improved, and the electrical performance of a circuit board is further ensured.

Description

Metal foil, circuit boards, copper-clad laminates, battery negative electrode materials and batteries

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to the Chinese patent application filed with the Patent Office of China on December 25, 2023, with application number 202311794924.9 and invention name “Metal foil, circuit board, copper-clad laminate, negative electrode material for battery and battery”, and the Chinese patent application filed with the Patent Office of China on February 1, 2024, with application number 202410148740.3 and invention name “Metal foil, circuit board, copper-clad laminate, negative electrode material for battery and battery”, the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The present application relates to the technical field of electrolytic copper foil, and in particular to metal foil, circuit boards, copper-clad laminates, negative electrode materials for batteries, and batteries. Background Art

[0004] Metal foil is a vital material widely used in the electronics industry, particularly in copper-clad laminates and printed circuit boards. It plays a crucial role in conducting circuits and interconnecting components within printed circuit boards, and has been called the "neural network" for signal and power transmission and communication in electronic products. It is also a crucial raw material in chip packaging and new energy batteries.

[0005] With the development of electronic information technology, the use of multi-layer, complex, or high-density, fine-circuit PCBs is increasing in high-precision, miniaturized electronic products. High-precision electronic metal foil or double-sided roughened electrolytic metal foil is typically used for the inner layers of high-density, fine-circuit PCBs or multi-layer, complex PCBs. However, it has been found that traditional metal foil is prone to excessive etching when etching circuits, resulting in an inverted trapezoidal shape. This can lead to the following problems: 1) The circuit spacing becomes wider, reducing the contact area between the circuit and the substrate, thereby weakening the bonding strength between the circuit and the substrate. The circuit is easily delaminated from the circuit substrate, resulting in circuit failure or unstable circuit performance, and reducing product yield; 2) The original circuit area is reduced, thereby reducing signal transmission efficiency.

[0006] Summary of the Invention

[0007] The present application provides a metal foil, a circuit board, a copper-clad laminate, a negative electrode material for a battery, and a battery. By designing the protrusions on the surface of the metal foil and the size structure of its average grains, the metal foil has good corrosion resistance, which can prevent side corrosion of the circuit, effectively improve the product yield, and thus ensure the electrical performance of the circuit board.

[0008] In order to solve the above technical problems, an embodiment of the present application provides a metal foil, which includes a first surface and a second surface relative to each other, and a number of protrusions on the second surface, the maximum vertical height h of the protrusions is 0.2 to 3 μm, and the average grain size of the metal grains in the protrusions is 0.05 to 1.5 μm.

[0009] As one optional solution, the maximum vertical height of the protrusion is 0.5 to 2 μm, and the average grain size of the metal grains in the protrusion is 0.1 to 1.2 μm.

[0010] As an optional solution, the overall thickness of the metal foil is 3 to 15 μm.

[0011] As an optional solution, the metal foil further includes a titanium roller surface or a non-titanium roller surface.

[0012] As an optional solution, the metal foil further includes an anti-oxidation layer, and the anti-oxidation layer is provided on the first surface and / or the second surface.

[0013] As an optional solution, the metal foil further includes a peeling layer, and the peeling layer is provided on the first surface.

[0014] As an optional solution, the metal foil further includes a carrier layer, and the carrier layer is provided on a side of the release layer away from the first surface.

[0015] As one optional solution, the metal material of the metal foil is any one of nickel, titanium, copper, silver, gold, platinum, iron, cobalt, chromium, tungsten, molybdenum, aluminum, magnesium, potassium, sodium, calcium, strontium, barium, germanium, antimony, lead, indium and zinc; or,

[0016] The metal material is an alloy formed by at least two of nickel, titanium, copper, silver, gold, platinum, iron, cobalt, chromium, tungsten, molybdenum, aluminum, magnesium, potassium, sodium, calcium, strontium, barium, germanium, antimony, lead, indium and zinc.

[0017] As an optional solution, the metal foil further includes a dielectric layer, and the dielectric layer is disposed on the surface of at least one of the metal foils.

[0018] As one optional solution, the material of the dielectric layer is selected from at least one of polyimide, epoxy resin, modified epoxy resin, modified acrylic resin, cyanate resin, polyethylene terephthalate, polybutylene terephthalate, polyethylene, polyethylene naphthalate, polystyrene, polyvinyl chloride, polysulfone, polyphenylene sulfide, polyetheretherketone, polyphenylene oxide, polytetrafluoroethylene, liquid crystal polymer, polyoxadiazole, epoxy glass cloth, BT resin, metal, and ceramic.

[0019] As an optional solution, the metal foil further includes an adhesive layer, and the adhesive layer is provided on the surface of at least one of the metal foils.

[0020] As one optional solution, the material of the adhesive layer is selected from at least one of polystyrene, vinyl acetate, polyester, polyethylene, polyamide, rubber or acrylic thermoplastic resins, phenolic, epoxy, thermoplastic polyimide, urethane, melamine or alkyd thermosetting resins, BT resin, and ABF resin.

[0021] Another embodiment of the present application provides a copper-clad laminate comprising the metal foil.

[0022] Another embodiment of the present application provides a circuit board, the circuit board comprising the metal foil or the copper-clad laminate as described above. Another embodiment of the present application provides a semiconductor material, the semiconductor material being prepared from the metal foil as described above.

[0023] Yet another embodiment of the present application provides a negative electrode material for a battery, the negative electrode material comprising the metal foil as described above and an electrode active material coated on a surface of the metal foil.

[0024] Yet another embodiment of the present application provides a battery, comprising the negative electrode material as described above.

[0025] Compared with the prior art, the embodiments of the present application have the following advantages:

[0026] (1) The present invention can adjust the depth of the protrusion embedded in the substrate by designing the height of the protrusion on the metal foil, and design the average grain size of the protrusion on the metal foil to prevent the etching solution from excessively etching the circuit and causing side etching to form an inverted trapezoidal circuit;

[0027] (2) The metal foil provided in the present application includes a first surface and a second surface relative to each other, and a plurality of protrusions are provided on the second surface. When the maximum vertical height of the protrusions is 0.2 to 3 μm and the average grain size of the metal grains in the protrusions is 0.05 to 1.5 μm, on the one hand, it can avoid the separation of the circuit and the substrate, thereby improving the peeling strength between the circuit and the substrate; on the other hand, it ensures the stability of the circuit signal transmission, effectively improves the product yield, and ensures the electrical performance of the circuit board. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] FIG1 is a schematic diagram of a metal foil in one embodiment of the present application;

[0029] FIG2 is a schematic diagram of a metal foil in one embodiment of the present application;

[0030] FIG3 is a schematic diagram of a metal foil in one embodiment of the present application;

[0031] Reference numerals: 1, metal foil; 11, second surface; 111, protrusion; 1111, metal grain; 2, anti-oxidation layer; 3, peeling layer; 4, carrier layer; h represents the height of the protrusion. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. The purpose of providing these embodiments is to make the disclosure of this application more thorough and comprehensive. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0033] In the description of this application, the terms "first," "second," "third," etc. are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, a feature specified as "first," "second," "third," etc. may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise specified, "plurality" means two or more.

[0034] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be a communication between the two elements. The terms "vertical", "horizontal", "left", "right", "up", "down" and similar expressions used herein are for illustrative purposes only, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application. The term "and / or" used herein includes any and all combinations of one or more related listed items. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0035] In the description of this application, it should be noted that, unless otherwise defined, all technical and scientific terms used in this application have the same meanings as those commonly understood by those skilled in the art. The terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood by those skilled in the art in specific circumstances.

[0036] Example 1

[0037] Please refer to Figure 1, which conceptually shows a schematic structural diagram of the metal foil provided in an embodiment of the present application. The metal foil includes a first surface and a second surface 11 relative to each other. A number of irregular protrusions 111 are prominently displayed on the second surface 11 of the metal foil in Figure 1 of this embodiment, and it is conceptually demonstrated that the protrusions 111 are composed of tiny metal grains 1111 piled up, and the distribution of metal grains in the protrusions is also displayed.

[0038] In the embodiment of the present application, in order to prevent the etching solution from excessively etching the circuit to make it in an inverted trapezoidal shape, resulting in the widening of the circuit spacing, thereby reducing the contact area between the circuit and the substrate, reducing the bonding force between the circuit and the substrate, and easily causing delamination from the circuit substrate, reducing the efficiency of signal transmission, and reducing the yield rate of the product, the present application has made improvements to the metal foil for preparing the circuit. Specifically, the metal foil includes a first surface and a second surface 11 relative to each other, and there are a plurality of protrusions 111 on the second surface 11. The maximum vertical height of the protrusion 111 is 0.2 to 3 μm, and the average grain size 1111 of the protrusion is 0.05 to 1.5 μm. In the present application, a protrusion refers to a structure composed of the highest point of a protrusion structure (or a protrusion structure) and the lowest points of the two adjacent sides, as shown in 111 in Figure 1. The protrusions shown in the scanning electron microscope image are independent; the protrusions in the metal foil cross-section image are also independent.

[0039] The average grain size described in this application can be obtained by measuring with professional instruments, and the average grain size can be obtained by EBSD (electron backscatter diffraction) or SEM measurement.

[0040] It should be noted that the shape “O” in FIG. 1 conceptually illustrates the distribution of the metal foil grains. However, in the actual metal foil, the metal grains are not in the shape of “O” but in the shape of irregular polygons.

[0041] It should be noted that the vertical height of the protrusions and the overall thickness of the metal foil can be measured by scanning electron microscopy (SEM) or EBSD.

[0042] After extensive testing and analysis, the applicant discovered that the deeper the protrusions are embedded into the substrate and the larger the grain size at the embedded location, the less susceptible they are to side etching. However, when the maximum vertical height h of the protrusions on the second side of the metal foil exceeds 3 μm, the roughness of the metal foil increases, exacerbating the skin effect and thus affecting signal transmission. When the average grain size of the metal exceeds 1.5 μm, the etching rate decreases, resulting in incomplete etching and affecting product quality. Therefore, designing the size structure of the metal foil protrusions and the average grain size is particularly important.

[0043] In the embodiments of this application, by adjusting the depth of the protrusion embedded in the substrate and the size of the protrusion grains, specifically designing the maximum vertical height h of the protrusion to be 0.2-3 μm and the average grain size a of the protrusion to be 0.05-1.5 μm, this prevents the etching solution from over-etching the circuit, causing undercuts and forming inverted trapezoidal circuits. This prevents separation of the circuit from the substrate, improving the peel strength between the circuit and the substrate. Furthermore, it ensures the stability of the circuit signal transmission, effectively improving the product yield rate. Optionally, the maximum vertical height h of the protrusion described in the present application can be 0.2μm, 0.5μm, 0.6μm, 0.8μm, 1.0μm, 1.2μm, 1.4μm, 1.6μm, 1.8μm, 2.0μm, 2.2μm, 2.4μm, 2.6μm, 2.8μm, 3μm or an interval formed by a combination of the above numbers; the average grain size a of the protrusion described in the present application can be 0.05μm, 0.06μm, 0.08μm, 0.09μm, 0.1μm, 0.2μm, 0.4μm, 0.6μm, 0.8μm, 1.0μm, 1.1μm, 1.2μm, 1.3μm, 1.4μm, 1.5μm or an interval formed by a combination of the above numbers.

[0044] As an optional embodiment of the present application, the maximum vertical height of the protrusion is 0.5 to 2 μm, and the average grain size of the metal grains in the protrusion is 0.1 to 1.2 μm.

[0045] In order to further prevent the etching solution from over-etching the circuit to make it an inverted trapezoid, the embodiment of the present application has improved the metal foil for preparing the circuit. Under certain etching conditions, the metal foil of the present application adjusts the etching speed through different grain sizes to prevent side etching.

[0046] In an embodiment of the present application, in order to prevent the etching solution from over-etching the circuit to make it an inverted trapezoid, the present application improves the metal grains in the metal foil protrusions used to prepare the circuit, which can make the metal foil have good corrosion resistance and prevent the circuit from undergoing side corrosion, thereby effectively preventing the etching solution from over-etching the metal circuit to make it an inverted trapezoid, effectively improving the quality of the metal foil and ensuring the electrical performance of the circuit board.

[0047] In order to further prevent the occurrence of side erosion and improve the peeling force between the metal foil and the substrate, the present application studied the number of protrusions on the second surface of the metal foil and found that when the number of protrusions is 0.1×10 3 pieces / mm~3×10 3 When the number of protrusions is within the range of 0.1×10 / mm, the peeling force between the prepared circuit and the substrate is higher. 3 pieces / mm, 0.4×10 3pieces / mm, 0.8×10 3 pieces / mm, 1×10 3 pieces / mm, 1.5×10 3 pieces / mm, 1.8×10 3 pieces / mm, 2×10 3 pieces / mm, 2.4×10 3 pieces / mm, 2.8×10 3 pieces / mm, 3.0×10 3 The interval is composed of pieces / mm or a combination of any of the above numbers. The metal foil of the embodiment of the present application is suitable for high-frequency circuits. The overall thickness of the metal foil will affect its use in high-precision small or lightweight electronic products, and the thickness should not be too thick. In an optional embodiment, in order to ensure the effectiveness of the metal foil, the overall thickness of the metal foil in this embodiment is 3 to 15 μm, for example, it can be 3 microns, 4 microns, 5 microns, 6 microns, 8 microns, 10 microns, 12 microns, 13 microns, 14 microns, 15 microns, etc. Of course, the overall thickness of the metal foil can be set according to the actual product requirements, and no further details will be given here.

[0048] For example, in one embodiment, the metal foil of the present application can be obtained by the following method: forming a metal foil 1 on a titanium roller by chemical deposition (for example, electroplating), the metal foil having a first surface and a second surface 11 relative to each other, and selecting the second surface of the metal foil for roughening by a roughening process, forming a plurality of protrusions 111 on the second surface, thereby forming a roughened surface. The maximum vertical height of the protrusion is 0.2 to 3 μm, and the average grain size of the metal grains 1111 in the protrusion is 0.05 to 1.5 μm. Among them, among the average grain size of the metal gold grains 1111 in the protrusion, the proportion of the average grain size of 0.6 to 1.0 μm is about 60%-90%, and its peel strength is higher.

[0049] A represents the metal foil product of the embodiment of the present application, and 6 metal foil samples A1, A2, A3, A4, A5, and A6 are randomly selected for comparison with comparative example B. The parameters of each metal sample are shown in Table 1 below:

[0050] Table 1: Parameters of various metal samples

[0051] Note: In this embodiment, the average grain size of the metal is obtained by the following method: an arbitrary length is taken on the cross-sectional view of the metal foil, and the average grain size (area-weighted mean) including all protrusions within the sampling length is measured by EBSD or SEM.

[0052] Metal foil samples A and B were fabricated into 50cm x 60cm circuit board test panels. Fine lines with a line width and line spacing of 25μm / 25μm and a line height of 25μm were produced using a modified semi-additive process (mSAP). Metallographic sections were used to examine the prepared lines to see if they exhibited an inverted trapezoidal shape.

[0053] Peel strength test method: After laminating the second surface of the metal foil of this application to polypropylene (PP) using a Korean press #66, the carrier layer was peeled off. Electroplating was performed on the metal foil to thicken it by 15 μm, followed by baking to remove moisture. Using a 5 mm wide strip, the bond strength between the copper foil and PP was tested at a 90° angle. The test results are shown in the following table:

[0054] Table 2: Circuit etching results of various metal samples

[0055] As can be seen from the above table, the present application prevents the metal foil from being over-etched by the solution when preparing fine circuits by adjusting the vertical height h of the metal foil protrusions and the distribution of the metal foil grain size in the protrusions, thereby preventing the circuits from forming an inverted trapezoid. It also improves the peel strength between the metal foil and the substrate, avoiding the circuit from easily delaminating from the circuit substrate.

[0056] Furthermore, in the above embodiment, the metal foil further includes a titanium roller surface or a non-titanium roller surface.

[0057] In the embodiment of the present application, it is considered that during the application process, the outer surface of the metal foil is easily contaminated by objects such as moisture and dust in the air, and then an oxidation reaction occurs. For example, when the metal foil is in a high-temperature pressing process, the oxidation reaction causes pits and protrusions to form on the surface of the extremely thin metal foil during the pressing process, resulting in an uneven surface of the metal foil. This may lead to large line transmission losses in subsequent applications, and may also cause poor adhesion between the metal foil and application carriers such as circuit substrates when pressed, causing problems such as the metal foil tilting, bubbling, and wrinkling. In addition, it is also possible that oxidation points fall off during the pressing process and adhere to the surface of the pressing plate of the press, causing contamination to the press, thereby affecting the subsequent pressing process. Therefore, in the embodiment of the present application, the metal foil also includes an anti-oxidation layer, and the anti-oxidation layer is provided on the first surface or / and the second surface. The anti-oxidation layer protects the outer surface of the metal foil from contamination by moisture, dust, and other particles in the air, maintaining a relatively dry and clean surface. It is also less susceptible to oxidation, effectively protecting the foil and simplifying environmental requirements for its transportation and storage, reducing the number of pre-use cleaning steps. The anti-oxidation layer is made of at least one of nickel, copper, zinc, and / or an alloy of at least one of these metals.

[0058] In an embodiment of the present application, the metal foil further includes a release layer, which is disposed on the first surface. The function of the release layer is to separate the metal foil by peeling, facilitating the subsequent fabrication of the circuit. The release layer is made of a metallic material or a non-metallic material. The metallic material includes any one or more of molybdenum, titanium, and niobium; the non-metallic material includes silicon, graphite, an organic polymer material, etc. When the release layer is a non-metallic material, the release layer includes a silicone-free release layer, a silicone oil release layer, or a nitrogen release layer. The release layer can be formed by applying and drying a release agent. In one embodiment, the release agent can include HDPE (high-density polyethylene) and PMA (propylene glycol methyl ether acetate) solvent. When using the two aforementioned release agents, the mass ratio of HDPE:PMA can be selected to be (1-5):7. In another embodiment, the release agent can include a fluorine-based release agent and a solvent; wherein the volume ratio of the fluorine-based release agent:solvent can be selected to be (5-30):1. It can be understood that there is no special restriction on the types of the above solvents, and conventional release agent solvents in the field can be selected, such as butanone, which does not constitute a limitation on the present application. Optionally, when the material of the peeling layer is a metal material, the thickness of the peeling layer is 2 to 100 nm; or, when the material of the peeling layer is a non-metallic material, the thickness of the peeling layer is less than or equal to 1 μm. The specific thickness of the peeling layer can be set according to actual use requirements, and no further details are given here. The structural setting of the peeling layer in the application embodiment can ensure appropriate adhesive strength, while retaining a certain adhesive ability, so that the metal foil will not be delaminated during the hot pressing process.

[0059] In an embodiment of the present application, the metal foil further comprises a carrier layer, which is disposed on a side of the release layer away from the first surface and primarily serves as a support. The carrier layer is made of a metal material, and the metal material comprises at least one of metal elements such as copper, aluminum, zinc, nickel, chromium, iron, silver, and gold.

[0060] It can be understood that the thickness of the carrier layer will affect the overall thickness of the metal foil. In order to ensure the overall performance of the metal foil and prevent the metal foil from being too thick, in the embodiment of the present application, the thickness of the carrier layer needs to be set according to actual usage requirements, and no further details will be given here.

[0061] In an embodiment of the present application, the metal material of the metal foil is a single metal material, which can be selected from any one of nickel, titanium, copper, silver, gold, platinum, iron, cobalt, chromium, tungsten, molybdenum, aluminum, magnesium, potassium, sodium, calcium, strontium, barium, germanium, antimony, lead, indium and zinc; in addition, the metal material of the metal foil can also be an alloy, for example, an alloy formed by at least two of nickel, titanium, copper, silver, gold, platinum, iron, cobalt, chromium, tungsten, molybdenum, aluminum, magnesium, potassium, sodium, calcium, strontium, barium, germanium, antimony, lead, indium and zinc, which is set according to actual product design requirements and is not specifically limited here.

[0062] In an embodiment of the present application, the metal foil further includes a dielectric layer, and the dielectric layer is disposed on the surface of at least one of the metal foils.

[0063] Optionally, the material of the dielectric layer is selected from at least one of polyimide, epoxy resin, modified epoxy resin, modified acrylic resin, cyanate resin, polyethylene terephthalate, polybutylene terephthalate, polyethylene, polyethylene naphthalate, polystyrene, polyvinyl chloride, polysulfone, polyphenylene sulfide, polyetheretherketone, polyphenylene oxide, polytetrafluoroethylene, liquid crystal polymer, polyoxadiazole, epoxy glass cloth, BT resin, metal, and ceramic.

[0064] In an embodiment of the present application, the metal foil further includes an adhesive layer, and the adhesive layer is disposed on the surface of at least one of the metal foils.

[0065] Optionally, the material of the adhesive layer is selected from at least one of polystyrene, vinyl acetate, polyester, polyethylene, polyamide, rubber or acrylic thermoplastic resins, phenolic, epoxy, thermoplastic polyimide, urethane, melamine or alkyd thermosetting resins, BT resin, and ABF resin.

[0066] It can be understood that when the metal foil of the present application contains an anti-oxidation layer, the dielectric layer or adhesive layer can be arranged on the anti-oxidation layer; when the metal foil of the present application contains a peeling layer and / or a carrier layer, the dielectric layer or adhesive layer is arranged on the surface of the metal foil away from the peeling layer and / or the carrier layer.

[0067] Example 2

[0068] This embodiment provides a copper-clad laminate, which includes the metal foil described above.

[0069] Example 3

[0070] This embodiment provides a circuit board, which includes the metal foil or copper-clad laminate as described above.

[0071] Example 4

[0072] This embodiment provides a semiconductor material, which is prepared from the metal foil described above.

[0073] Example 5

[0074] This embodiment provides a negative electrode material for a battery. The negative electrode material includes the metal foil as described above and an electrode active material coated on a surface of the metal foil.

[0075] Example 6

[0076] This embodiment provides a battery, which includes the negative electrode material described above.

[0077] The metal foil, circuit board, copper-clad laminate, semiconductor material, negative electrode material for battery, and battery provided in the embodiments of the present application have the beneficial effects of at least one of the following:

[0078] (1) By designing the size structure of the metal foil protrusions and their average grain size, the present application can adjust the depth of the protrusions embedded in the substrate, thereby preventing the etching solution from excessively etching the circuit and causing side etching to form an inverted trapezoidal circuit;

[0079] (2) The metal foil provided in the present application includes a first surface and a second surface relative to each other, and the second surface has a plurality of protrusions. When the maximum vertical height of the protrusions is 0.2 to 3 μm and 0.05 to 1.5 μm, on the one hand, it can prevent the circuit from being separated from the substrate and improve the peeling strength between the circuit and the substrate. On the other hand, it ensures the stability of the circuit signal transmission, effectively improves the product yield, and ensures the electrical performance of the circuit board.

[0080] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A metal foil, characterized in that, The metal foil includes opposite first and second surfaces. There are a number of protrusions on the second surface. The maximum vertical height of the protrusions is 0.2 to 3 μm, and the average grain size of the metal grains in the protrusions is 0.05 to 1.5 μm.

2. The metal foil according to claim 1, wherein The maximum vertical height of the protrusions is 0.5 to 2 μm, and the average grain size of the metal grains in the protrusions is 0.1 to 1.2 μm.

3. The metal foil according to claim 1, wherein The overall thickness of the metal foil is 3 to 15 μm.

4. The metal foil according to any one of claims 1 to 3, characterized in that, The metal foil further includes a titanium roll surface or a non-titanium roll surface.

5. The metal foil according to claim 1, wherein The metal foil further includes an antioxidant layer provided on the first surface and / or the second surface.

6. The metal foil according to claim 1, wherein The metal foil further includes a release layer provided on the first surface.

7. The metal foil according to claim 6, wherein The metal foil further includes a carrier layer provided on a side of the release layer away from the first surface.

8. The metal foil according to claim 7, wherein, The metal material of the metal foil is any one of nickel, titanium, copper, silver, gold, platinum, iron, cobalt, chromium, tungsten, molybdenum, aluminum, magnesium, potassium, sodium, calcium, strontium, barium, germanium, antimony, lead, indium, and zinc; or, The metal material is an alloy formed by at least two of nickel, titanium, copper, silver, gold, platinum, iron, cobalt, chromium, tungsten, molybdenum, aluminum, magnesium, potassium, sodium, calcium, strontium, barium, germanium, antimony, lead, indium, and zinc.

9. The metal foil according to any one of claims 1 to 8, characterized in that, The metal foil further includes a dielectric layer provided on the surface of at least one of the metal foils.

10. The metal foil according to claim 9, characterized in that, The dielectric layer material is selected from at least one of polyimide, epoxy resin, modified epoxy resin, modified acrylic resin, cyanate resin, polyethylene terephthalate, polybutylene terephthalate, polyethylene, polyethylene naphthalate, polystyrene, polyvinyl chloride, polysulfone, polyphenylene sulfide, polyether ether ketone, polyphenylene ether, polytetrafluoroethylene, liquid crystal polymer, polyoxalyl urea, epoxy glass cloth, BT resin, metal, and ceramic.

11. The metal foil according to any one of claims 1 to 8, characterized in that, The metal foil further includes an adhesive layer provided on the surface of at least one of the metal foils.

12. The metal foil according to claim 11, characterized in that, The material of the adhesive layer is selected from at least one of polystyrene-based, vinyl acetate-based, polyester-based, polyethylene-based, polyamide-based, rubber-based, or acrylate-based thermoplastic resins, phenolic-based, epoxy-based, thermoplastic polyimide, urethane-based, melamine-based, or alkyd-based thermosetting resins, BT resin, and ABF resin.

13. A copper-clad laminate, characterized in that, It includes the metal foil according to any one of claims 1 to 12.

14. A circuit board, characterized in that, The circuit board includes the metal foil according to any one of claims 1 to 8 or the copper-clad laminate according to claim 13.

15. A semiconductor material, characterized in that, The semiconductor material is prepared from the metal foil according to any one of claims 1 to 8.

16. A negative electrode material applied to a battery, characterized in that, The negative electrode material includes the metal foil according to any one of claims 1 to 8 and an electrode active material coated on the surface of the metal foil.

17. A battery, characterized in that, The battery includes the negative electrode material according to claim 16.

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