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

Abstract

Disclosed in the present application are a metal foil, a circuit board, a copper-clad laminate, a battery negative electrode material, and a battery. The metal foil comprises a first surface and a second surface which are opposite to one another, a plurality of protrusions are provided on the second surface, and the ratio a of the maximum width to the maximum vertical height of the protrusions satisfies 1 / 5≤a≤1 / 2. In the metal foil, the circuit board, the copper-clad laminate, the battery negative electrode material, and the battery provided in the embodiments of the present application, defining the shape and size of the protrusions on the second surface of the metal foil effectively increases the peel force between the metal foil and a substrate and reduces the degradation rate of the circuit board, thus increasing the product yield rate of the circuit board.

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 202311794928.7 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 202410148733.3 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 products such as flexible 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 rapid development of microelectronics technology, new energy batteries and other technologies, the bonding strength between metal foil and circuit board is a key factor affecting the quality of circuit boards. When the bonding strength between metal foil and circuit substrate is low, the metal circuit and substrate will be delaminated during the application process of the etched circuit board, and the circuit will be separated from the substrate, resulting in the scrapping of the circuit board. Therefore, how to improve the bonding strength between metal foil and circuit substrate has become a technical problem that needs to be solved urgently by those skilled in the art.

[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. The shape and size of the protrusions on the surface of the metal foil are limited, which effectively improves the peeling force between the metal foil and the substrate, thereby improving the product yield 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; a number of protrusions are distributed on the second surface, and the ratio a between the maximum width and height of the protrusions satisfies 1 / 5≤a≤1 / 2.

[0009] As an optional solution, the maximum width of some of the protrusions is located at 1 / 2 of the protrusion height.

[0010] As an optional solution, the maximum width of some of the protrusions is located at 1 / 4 of the protrusion height.

[0011] As an optional solution, the maximum width of some of the protrusions is located at 3 / 4 of the protrusion height.

[0012] As an optional solution, the maximum width of some of the protrusions is located at the bottom of the protrusion height.

[0013] As an optional solution, the protrusions with the maximum width located at the bottom of the protrusion height account for 60%-90% of the total number of protrusions.

[0014] As one optional solution, the protrusions with the maximum width located at 1 / 4 of the protrusion height account for 40%-50% of the total number of protrusions.

[0015] As one optional solution, the protrusions with the maximum width located at ¾ of the protrusion height account for 30%-40% of the total number of protrusions.

[0016] As one optional solution, the protrusions with the maximum width located at 1 / 2 of the protrusion height account for 5%-40% of the total number of protrusions.

[0017] As one of the optional solutions, the sum of the proportions of the protrusions with the maximum width located at the bottom, 1 / 4, 1 / 2, and 3 / 4 is less than or equal to 100%.

[0018] As one of the optional solutions, the maximum width of the protrusion is 0.4-1 μm.

[0019] The maximum width is the maximum width of the protrusion measured at a horizontal position.

[0020] 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,

[0021] 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.

[0022] As an optional solution, the metal foil further includes a titanium roller surface or a non-titanium roller surface.

[0023] As an optional solution, the metal foil further includes an anti-oxidation layer, and the anti-oxidation layer is arranged on the third electroplated layer away from the first surface and / or the second surface.

[0024] As an optional solution, the metal foil further includes a peeling layer, and the peeling layer is provided on the first surface.

[0025] 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.

[0026] Another embodiment of the present application provides a copper-clad laminate, which includes the metal foil as described above.

[0027] As an optional solution, the copper-clad laminate further includes a dielectric layer, and the dielectric layer is provided on the one side of at least one of the metal foils.

[0028] As one optional solution, the material of the dielectric layer is selected from at least one of polyimide, modified epoxy resin, modified acrylic 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, and BT resin.

[0029] As an optional solution, the copper-clad laminate further includes a second adhesive layer, and the second adhesive layer is provided on the one side of the metal foil.

[0030] As one optional solution, the material of the second 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.

[0031] Another embodiment of the present application provides a circuit board, which includes the metal foil as described above or the copper-clad laminate as described above.

[0032] Another embodiment of the present application provides a semiconductor material, which is prepared from the metal foil as described above.

[0033] Another embodiment of the present application provides a negative electrode material for a battery, wherein the negative electrode material includes the metal foil as described above and an electrode active material coated on a surface of the metal foil.

[0034] Another embodiment of the present application provides a battery, which includes the negative electrode material as described above.

[0035] Compared with the prior art, the embodiments of the present application have the following advantages:

[0036] The present application conducts a detailed study on the protrusions on the second surface of the metal foil. When the ratio a of the maximum width W of the protrusion / the maximum vertical height L is less than 1 / 5, metal powder is easily generated at the top of the protrusion during the formation of the protrusion, reducing the bonding force between the protrusion and the substrate; when the ratio a of the maximum width W of the protrusion / the maximum vertical height L is greater than 1 / 2, the product does not have the embedding ability, resulting in a reduction in the embedding effect of the protrusion and an inability to bond with the substrate. Therefore, the present application improves the peeling force between the metal foil and the substrate by adjusting the ratio between the maximum diameter of the protrusion and its maximum vertical height, and designs the ratio a between the maximum width W and the maximum vertical height L of the protrusion within the range of [1 / 5, 1 / 2], thereby obtaining a protrusion that can improve the peeling force between the metal foil and the substrate. At the same time, it is not easy to generate metal residue during the circuit etching process, which leads to the scrapping of the circuit board, effectively improving the quality of the metal foil, thereby improving the product yield of the circuit board and reducing the degradation rate of the circuit board. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] FIG1 is a schematic diagram of a metal foil in one embodiment of the present application;

[0038] FIG2 is a schematic diagram of a metal foil in one embodiment of the present application;

[0039] FIG3 is a schematic diagram of a metal foil in one embodiment of the present application;

[0040] Reference numerals:

[0041] Among them, 1, metal foil; 11, first surface; 12, second surface; 121, protrusion; 2, anti-oxidation layer; 3, peeling layer; 4, carrier layer, W represents the maximum width of the measured protrusion, and L represents the height of the protrusion. DETAILED DESCRIPTION

[0042] 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.

[0043] 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 such features. In the description of this application, unless otherwise specified, "plurality" means two or more.

[0044] 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.

[0045] 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.

[0046] Example 1

[0047] Please refer to Figure 1, which conceptually shows a schematic structural diagram of a metal foil provided for an embodiment of the present application, wherein the metal foil 1 includes a first surface 11 and a second surface 12 relative to each other; the second surface 12 of the metal foil in Figure 1 highlights several irregular protrusions 121, where W represents the maximum width of the protrusion and L represents the maximum vertical height of the protrusion.

[0048] In this application, a protrusion refers to a structure consisting of the highest point of a protrusion structure (or the lowest points of two adjacent sides), as shown in 121 in Figure 1. The protrusions shown in the scanning electron microscope image are independent of each other; the protrusions shown in the metal foil cross-section image are also independent of each other.

[0049] It should be noted that for metal foil, taking copper foil as an example, in printed circuit boards, the surface of the copper foil needs to be roughened and reinforced to enhance its bonding strength with the substrate. This ensures good adhesion to the circuit board substrate during use and prevents it from falling off. In the embodiments of this application, the term "roughened protrusions" refers to fine, nodular metal particles formed by depositing metal on the surface of the metal foil using a conventional surface roughening process.

[0050] To improve the bonding strength between the metal foil and the circuit substrate, the present application provides a roughened surface by providing several protrusions on the side of the metal foil where it is pressed against the circuit substrate. Specifically, during research into the protrusions on the roughened surface of the metal foil, the applicant, through extensive experimental analysis, discovered that the shape of the protrusions affects the bonding strength between the metal foil and the substrate. When the ratio (a) of the protrusion's maximum width W / maximum vertical height L is less than 1 / 5, metal powder is easily generated at the protrusion's tip during formation, reducing the bonding strength between the protrusion and the substrate. When the ratio (a) of the protrusion's maximum width W / maximum vertical height L is greater than 1 / 2, the product lacks embeddability, resulting in a reduced embedding effect and an inability to bond with the substrate.

[0051] The height and width of the protrusions described in the present application can be obtained by measuring with a profilometer, or by directly measuring the SEM image of a metal foil slice.

[0052] The present embodiment adjusts the ratio between the maximum width of the surface protrusions and their maximum vertical height to achieve protrusions that improve the peeling force between the metal foil and the substrate. Specifically, the present embodiment sets the ratio a between the maximum width W and the maximum vertical height L of the protrusions within the range of [1 / 5, 1 / 2]. This effectively improves the peeling force between the metal foil and the substrate, while also reducing the generation of metal residue during the circuit etching process, which could render the circuit board scrapped. This improves the product yield of the circuit boards.

[0053] It should be noted that the shape, size and quantity ratio of the above-mentioned protrusions can be measured by instruments, optionally by scanning electron microscopy (SEM) or EBSD (electron backscatter diffraction), and the subsequent metal foil thickness can be obtained by sample slicing.

[0054] It is understandable that the maximum width (maximum horizontal width) of the protrusion of the metal foil can be at any position of the protrusion, but it has been verified by the applicant that the ideal function of embedding the substrate can be formed only when the maximum width is at the following positions, for example: the maximum width of some of the protrusions is at 1 / 2 of the protrusion height, the maximum width of some of the protrusions is at 1 / 4 of the protrusion height, the maximum width of some of the protrusions is at 3 / 4 of the protrusion height, and the maximum width of some of the protrusions is at the bottom of the protrusion height (the bottom is the position where the protrusion is connected to the metal).

[0055] Understandably, the maximum width of the protrusions can affect subsequent product performance. In an alternative embodiment, to ensure the performance of the metal foil, the maximum width W of the protrusions in this embodiment is 0.4 to 1 μm, for example, 0.4 microns, 0.5 microns, 0.6 microns, 0.8 microns, 1 micron, etc. Of course, the maximum width of the protrusions can be adjusted based on actual product requirements, and further details will not be provided here.

[0056] It can be understood that the present application does not limit the height of the protrusion, but only limits the maximum width of the protrusion, which ranges from 0.4 to 1 μm. Therefore, the height of the protrusion only needs to satisfy the ratio a between the maximum width and height of the protrusion of 1 / 5≤a≤1 / 2 based on the width range to achieve the purpose of the present application.

[0057] Alternatively, in an optional embodiment, the maximum vertical height L of the protrusion in this embodiment may be 0.8 to 5 μm, for example, 0.8 microns, 1.2 microns, 1.5 microns, 2 microns, 3 microns, 4 microns, 5 microns, etc. Of course, the maximum vertical height of the protrusion can be set according to actual product requirements, as long as the ratio a between the maximum width and height of the protrusion is 1 / 5 ≤ a ≤ 1 / 2, and no further details are given here.

[0058] The size of the protrusions affects their ability to embed into the circuit substrate. The applicant's research has found that when the maximum width of the protrusions is 0.4μm to 1μm and the maximum vertical height is 0.8μm to 5μm, the protrusions can more effectively embed into the circuit substrate, improving the peeling force between the metal and the substrate. When the maximum width of the protrusions is less than 0.4μm and the maximum vertical height is less than 0.8μm, the product size is too small to achieve the desired embedding effect. When the maximum width of the protrusions is greater than 1μm and the maximum vertical height is greater than 5μm, the product size is too large, increasing the roughness of the roughened surface, affecting circuit signal transmission, and resulting in metal residue on the substrate during the circuit etching process, resulting in incomplete etching.

[0059] Understandably, the overall thickness of the metal foil will affect its use in high-precision, small, or lightweight electronic products. In an optional embodiment, to ensure the performance of the metal foil, the overall thickness of the metal foil in this embodiment is 1 to 5 μm, for example, 1 micron, 2 microns, 3 microns, 4 microns, 5 microns, etc. Of course, the overall thickness of the metal foil can be adjusted according to actual product requirements, and further details will not be provided here.

[0060] 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 (e.g., electroplating), the metal foil having a first surface and a second surface 11 opposite to each other, and roughening the second surface of the metal foil by a roughening process to form a plurality of protrusions 121 on the second surface, thereby forming a roughened surface; the maximum width of the roughened protrusions is 0.4 to 1 μm, and the height is 0.2 to 3 μm. The plurality of protrusions can refer to a number of protrusions of 0.1×10 3 pieces / mm~3×10 3 Optionally, the number of the protrusions 11 can be 0.1×10 3 pieces / mm, 0.4×10 3 pieces / 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 any combination of the above numbers.

[0061] In another embodiment, the maximum width of some of the protrusions is located at 1 / 2 of the protrusion height; the maximum width of some of the protrusions is located at 1 / 4 of the protrusion height; the maximum width of some of the protrusions is located at 3 / 4 of the protrusion height; and the maximum width of some of the protrusions is located at the bottom of the protrusion height. The protrusions with the maximum width located at the bottom of the protrusion height account for 60%-90% of the total number of protrusions, and / or the protrusions with the maximum width located at 1 / 4 of the protrusion height account for 40%-50% of the total number of protrusions, and / or the protrusions with the maximum width located at 3 / 4 of the protrusion height account for 30%-40% of the total number of protrusions, and / or the protrusions with the maximum width located at 1 / 2 of the protrusion height account for 5%-40% of the total number of protrusions. When all of the above protrusions are present, the total proportion of the above protrusions is less than or equal to 100%. In this embodiment, the metal foil under the above conditions has better peel strength or bonding force, which can meet the application of high-frequency and high-speed lines.

[0062] A represents the metal foil product of the embodiment of the present application, and six metal foil samples A1, A2, A3, A4, A5, and A6 are randomly selected for comparison with Example B. The parameters of each metal sample are shown in Table 1 below:

[0063] Table 1: Parameters of various metal samples

[0064] Metal foil samples A and B were prepared into 50cm×60cm circuit board test boards. A modified semi-additive process (mSAP) was used to produce fine lines with a line width and line spacing of 25μm / 25μm and a line height of 25μm. SEM was used to observe whether there was any metal residue.

[0065] 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:

[0066] Table 2: Peel force test results between various metal samples and substrates

[0067] As can be seen from the above table, the present application enhances the bonding force between the metal foil and the circuit substrate by adjusting the shape of the roughened protrusions on the roughened surface of the metal foil, thereby avoiding the phenomenon that when the bonding force between the metal foil and the circuit substrate is low, the metal circuit and the substrate will be delaminated during the application process of the etched circuit board, and the circuit will be separated from the substrate, resulting in the scrapping of the circuit board. There is no metal residue in the circuit etching process, which improves the product yield.

[0068] Furthermore, in the above embodiment, the metal foil also includes a titanium roller surface or a non-titanium roller surface, so that the metal foil is easily separated from the titanium roller surface or the non-titanium roller surface during the subsequent electroplating process.

[0069] In the above embodiment, the metal foil includes a first electroplating layer, a second electroplating layer and a third electroplating layer from top to bottom, and the first electroplating layer, the second electroplating layer and the third electroplating layer are stacked in sequence to form an integral metal foil structure.

[0070] 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, blistering, 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.

[0071] In an embodiment of the present application, the metal foil further includes a release layer, which is disposed on the side of the first electroplated layer away from the third electroplated layer. The function of the release layer is to separate the metal foil by peeling. 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, organic polymer materials, etc. When the release layer is a non-metallic material, it can be in the form of a release layer. 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 (1-5):7. In another embodiment, the release agent can include a fluorine-based release agent and a solvent; the volume ratio of the fluorine-based release agent:solvent can 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.

[0072] In an embodiment of the present application, the metal foil further includes a carrier layer, which is disposed on a side of the release layer away from the first electroplated layer and primarily serves as a support. The carrier layer is made of a metal material, and the metal material includes at least one of copper, aluminum, zinc, nickel, chromium, iron, silver, gold, and the like.

[0073] 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.

[0074] Example 2

[0075] This embodiment provides a circuit board, which includes the metal foil as described above or the copper-clad laminate of the present application.

[0076] Example 3

[0077] This embodiment provides a copper-clad laminate, which includes the metal foil described above.

[0078] Furthermore, the copper-clad laminate further includes a dielectric layer, and the dielectric layer is provided on the one side of at least one of the metal foils.

[0079] Furthermore, the material of the dielectric layer is selected from at least one of polyimide, modified epoxy resin, modified acrylic 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, and BT resin.

[0080] Furthermore, the copper-clad laminate further includes a second adhesive layer, and the second adhesive layer is provided on the one side of the metal foil.

[0081] Furthermore, the material of the second 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.

[0082] Example 4

[0083] This embodiment provides a semiconductor material, which is prepared from the metal foil described above.

[0084] Example 5

[0085] 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.

[0086] Example 6

[0087] This embodiment provides a battery, which includes the negative electrode material described above.

[0088] 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:

[0089] The present application conducts a detailed study on the protrusions on the second surface of the metal foil. When the ratio a of the maximum width W of the protrusion / the maximum vertical height L is less than 1 / 5, copper powder is easily generated at the top of the protrusion during the formation of the protrusion, reducing the bonding force between the protrusion and the substrate; when the ratio a of the maximum width W of the protrusion / the maximum vertical height L is greater than 1 / 2, the product does not have the embedding ability, resulting in a reduction in the embedding effect of the protrusion and an inability to bond with the substrate. Therefore, the present application improves the peeling force between the metal foil and the substrate by adjusting the ratio between the maximum diameter of the protrusion and its maximum vertical height, and designs the ratio a between the maximum width W and the maximum vertical height L of the protrusion within the range of [1 / 5, 1 / 2], thereby obtaining a protrusion that can improve the peeling force between the metal foil and the substrate, effectively improving the quality of the metal foil, thereby improving the product yield of the circuit board and reducing the degradation rate of the circuit board.

[0090] 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; a number of protrusions are distributed on the second surface, and the ratio a between the maximum width and the height of the protrusions satisfies 1 / 5 ≤ a ≤ 1 / 2.

2. The metal foil according to claim 1, wherein The maximum width of some of the protrusions is located at 1 / 2 of the protrusion height.

3. The metal foil according to claim 1, characterized in that, The maximum width of some of the protrusions is located at 1 / 4 of the protrusion height.

4. The metal foil according to claim 1, characterized in that, The maximum width of some of the protrusions is located at 3 / 4 of the protrusion height.

5. The metal foil according to claim 1, characterized in that, The maximum width of some of the protrusions is located at the bottom of the protrusion height.

6. The metal foil according to claim 2, wherein The protrusions with the maximum width located at 1 / 2 of the protrusion height account for 5% - 40% of the total number of protrusions.

7. The metal foil according to claim 3, characterized in that, The protrusions with the maximum width located at 1 / 4 of the protrusion height account for 40% - 50% of the total number of protrusions.

8. The metal foil according to claim 4, characterized in that, The protrusions with the maximum width located at 3 / 4 of the protrusion height account for 30% - 40% of the total number of protrusions.

9. The metal foil according to claim 5, characterized in that, The protrusions with the maximum width located at the bottom of the protrusion height account for 60% - 90% of the total number of protrusions.

10. The metal foil according to claim 1, characterized in that, The maximum width of the protrusions is 0.4 - 1 μm.

11. The metal foil according to claim 1, characterized in that, The metal foil further includes an antioxidant layer, and the antioxidant layer is provided on the first surface or / and the second surface.

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

13. The metal foil according to claim 1, wherein The metal foil further includes a carrier layer, and the carrier layer is provided on the side of the release layer away from the first surface.

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

15. The copper-clad laminate according to claim 14, wherein, The copper-clad laminate further includes a dielectric layer, and the dielectric layer is provided on at least one of the surfaces of the metal foil.

16. The copper-clad laminate according to claim 15, wherein, The dielectric layer material is selected from at least one of polyimide, modified epoxy resin, modified acrylic resin, polyethylene terephthalate, polybutylene terephthalate, polyethylene, polyethylene naphthalate, polystyrene, polyvinyl chloride, polysulfone, polyphenylene sulfide, polyether ether ketone, polyphenylene ether, polytetrafluoroethylene, liquid crystal polymer, polyoxalylurea, epoxy glass cloth, BT resin.

17. The copper-clad laminate according to claim 14, wherein The copper-clad laminate further includes a second adhesive layer, and the second adhesive layer is provided on one of the surfaces of the metal foil.

18. The copper-clad laminate according to claim 17, wherein The material of the second 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, ABF resin.

19. A circuit board, characterized in that, The circuit board includes the metal foil according to any one of claims 1 to 13 or the copper-clad laminate according to any one of claims 14 to 18.

20. A semiconductor material, characterized in that, The semiconductor material is prepared from the metal foil according to any one of claims 1 to 13.

21. 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 13 and an electrode active material coated on the surface of the metal foil.

22. A battery, characterized in that, The battery includes the negative electrode material according to claim 21.

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