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

Abstract

Disclosed in the present application are a metal foil, a circuit board, a copper-clad laminate, a negative-electrode material of a battery, and a battery. The metal foil comprises a first surface and a second surface opposite each other, wherein there are several protrusions on the second surface, and the protrusions include first-type protrusions and second-type protrusions; a ratio a of the maximum width to maximum vertical height of the first-type protrusions satisfies 1≤a≤4, and the first-type protrusions account for 50-90% of all the protrusions; and a ratio b of the maximum width to maximum vertical height of the second-type protrusions satisfies 1 / 5≤b≤1 / 3, and the second-type protrusions account for 10-70% of all the protrusions. In the metal foil, circuit board, copper-clad laminate, negative-electrode material of a battery, and battery provided in the embodiments of the present application, the proportion of spiky protrusions is reduced, the overall height of the protrusions is reduced, and the content of gently undulating protrusions is increased, thereby reducing the high-frequency transmission signal loss caused by a skin effect on the circuit board, effectively improving the quality of the metal foil, and guaranteeing the electrical performance 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 202311794922.X 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 202410148774.2 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 development of electronic information technology, the use of multi-layer, complex, or high-density, fine-circuit PCBs in high-precision, miniaturized electronic products is increasing. This has led to increasingly demanding performance requirements for metal foil used in high-frequency, high-speed copper-clad laminates. Metal foil needs to be bonded to an organic insulating material to form the copper-clad laminate. To improve the peel strength of the metal foil used in high-frequency, high-speed copper-clad laminates and prevent it from peeling during use, the foil surface is typically roughened to impart a certain degree of roughness. However, this rough surface can easily cause signal loss and even distortion. Therefore, improving peel strength and reducing signal loss are in conflict. This dual requirement complicates the production of metal foil for high-frequency, high-speed copper-clad laminates.

[0006] Therefore, how to design a metal foil for high-frequency and high-speed copper-clad laminates so that it has both low surface roughness and strong peel strength has become a technical problem that needs to be urgently solved by those skilled in the art.

[0007] Summary of the Invention

[0008] 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 protrusions on the second surface of the metal foil are divided into shapes and limited in number, thereby reducing the proportion of spike-shaped protrusions and increasing the proportion of protrusions with gently undulating shapes, thereby reducing the high-frequency transmission signal loss caused by the "skin effect" on the circuit board, effectively improving the quality of the metal foil, and ensuring the electrical performance of the circuit board.

[0009] In order to solve the above technical problems, an embodiment of the present application provides a metal foil, wherein the metal foil includes a first surface and a second surface opposite to each other, wherein the second surface has a plurality of protrusions, and the protrusions include a first type of protrusions and a second type of protrusions;

[0010] The ratio a between the maximum width and the maximum vertical height of the first type of protrusions satisfies 1≤a≤4, and the first type of protrusions account for 50-90% of all protrusions;

[0011] The ratio b between the maximum width and the maximum vertical height of the second type of protrusions satisfies 1 / 5≤b≤1 / 3, and the second type of protrusions account for 10-70% of all protrusions.

[0012] As one of the optional solutions, the total proportion of the first type of protrusions and the second type of protrusions is less than or equal to 100%.

[0013] As an optional solution, within any sampling length on any outer contour line of the metal foil, 3 to 8 first-type protrusions are provided between two adjacent second-type protrusions.

[0014] As one optional solution, the maximum height of the first type of protrusions is 0.05 to 0.7 μm; the maximum height of the second type of protrusions is 0.5 to 3 μm.

[0015] As an optional solution, the overall thickness of the metal foil is 1 to 15 μm.

[0016] As an optional solution, the metal foil further includes a titanium roller surface or a non-Ti roller surface.

[0017] 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.

[0018] As an optional solution, the metal foil further includes a peeling layer, and the peeling layer is provided on the first surface.

[0019] As an optional solution, the metal foil further includes a carrier layer, and the carrier layer is arranged on the release layer away from the first surface.

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

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] Yet another embodiment of the present application provides a battery, comprising the negative electrode material as described above.

[0030] Compared with the prior art, the embodiments of the present application have the following advantages:

[0031] (1) The present application divides the protrusions on the second surface of the metal foil into different shapes and limits their number. The first type of protrusions meeting the ratio of maximum width to maximum vertical height of 1≤a≤4 are designed to account for 50-90% of all protrusions, and the second type of protrusions meeting the ratio of maximum width to maximum vertical height of 1 / 5≤a≤1 / 3 are designed to account for 10-70% of all protrusions, thereby reducing the number of spike-like particles, reducing the overall height of the particles, and increasing the content of protrusions with gently undulating shapes.

[0032] (2) The metal foil composed of the first type of protrusions of a specific shape and the second type of protrusions of a specific shape reduces the depth of the protrusions embedded in the substrate, but increases the contact area between the protrusions and the substrate. Therefore, on the basis of ensuring the peel strength, the high-frequency transmission signal loss caused by the "skin effect" on the circuit board is reduced, the quality of the metal foil is effectively improved, and the electrical performance of the circuit board is guaranteed;

[0033] (3) The shape design of the second type of protrusion will make it embedded deeper in the substrate. The longer the time the part embedded in the substrate is corroded by the etching solution, the more likely it is to cause side corrosion of the circuit and ensure the yield rate of the circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] FIG1 is a schematic cross-sectional view of a metal foil in one embodiment of the present application;

[0035] FIG2 is a schematic cross-sectional view of a metal foil in one embodiment of the present application;

[0036] FIG3 is a schematic cross-sectional view of a metal foil in one embodiment of the present application;

[0037] Reference numerals:

[0038] Among them, 1. metal foil; 11. first surface; 12. second surface; 121. protrusion; 2. anti-oxidation layer; 3. peeling layer; 4. carrier layer. DETAILED DESCRIPTION

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] Example 1

[0044] 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 1 includes a plurality of protrusions 121 on a first surface 11 and a second surface 12 relative to each other. The metal foil in Figure 1 highlights a plurality of irregular protrusions 121, where W represents the maximum width of the protrusion and L represents the maximum vertical height of the protrusion.

[0045] In this application, a protrusion refers to a structure consisting of the highest point of a protrusion (or protrusion structure) and the lowest points on two adjacent sides, as shown in 121 in Figure 1. A scanning electron microscope image or EBSD (electron backscatter diffraction) image of a metal cross section shows that the protrusions are independent of each other within any sampling length; a metal foil cross-section image also shows that the protrusions are independent of each other.

[0046] It's important to note that metal foil typically requires a roughening treatment to ensure good adhesion to the circuit board substrate during use and prevent it from peeling off. Taking copper foil as an example, when high-speed, high-frequency AC signals are transmitted on the circuits of a printed circuit board, the current distribution within the copper foil is uneven, concentrating on the thin layer on the conductor's surface. This phenomenon is known as the skin effect. Research has shown that the higher the frequency of the transmitted signal, the more pronounced the skin effect. Therefore, high-speed, high-frequency signal transmission is concentrated on the surface of the copper foil. To reduce the adverse effects of the skin effect on signal transmission, the copper foil is required to have a low surface roughness.

[0047] However, in printed circuit boards, the copper foil surface needs to be roughened to enhance its bonding strength to the substrate. However, the greater the surface roughness of the copper foil, the greater the high-frequency signal transmission loss. To reduce signal transmission loss in high-frequency circuits, low-profile copper foil is traditionally used. However, this treatment leads to another problem: the lower the roughness of the copper foil, the lower the bond strength (peel strength) between the copper foil and the substrate.

[0048] It can be seen from this that if the roughness of the copper foil surface is too large, it will not be able to meet the signal fidelity requirements of high-speed and high-frequency AC signals transmitted on the circuits of the printed circuit board. In order to minimize the loss of high-frequency signal transmission, reducing the roughness of the copper foil surface will cause the bonding strength between the copper foil and the substrate to decrease. Therefore, the contradiction brought about by high or low roughness seems difficult to reconcile. This problem is also a technical problem that technical personnel in this field need to solve urgently.

[0049] In order to reasonably resolve the contradiction between the roughness and the skin effect, the present embodiment divides the protrusions on the second surface of the metal foil into different shapes and limits the number of protrusions. Specifically, the protrusions include but are not limited to two types, namely, the first type of protrusions and the second type of protrusions. In terms of shape, the ratio a between the maximum width W and the maximum vertical height L of the first type of protrusions satisfies 1≤a≤4, and the ratio b between the maximum width W and the maximum vertical height L of the second type of protrusions satisfies 1 / 5≤b≤1 / 3. It can be seen that the depth of the first type of protrusions embedded in the substrate is shallower than that of the second type of protrusions due to their shape and size limitations, and the depth of the second type of protrusions embedded in the substrate is deeper than that of the second type of protrusions due to their shape and size limitations. In terms of quantity, the first type of protrusions are shallower than that of the second type of protrusions. The first type of protrusions account for 50-90% of all type of protrusions, for example, it can be 50%, 55%, 60%, 63%, 66%, 69%, 70%, 80% or 90%. The second type of protrusions account for 10-70% of all type of protrusions, for example, it can be 10%, 20%, 21%, 22%, 26%, 30%, 40%, 50%, 60% or 70%. Through the above reasonable planning, the number of thorn-like particles is reduced, the height of the particles is reduced, and the content of protrusions with gently undulating shapes is increased. Although the depth of particles embedded in the substrate is reduced, the contact area between the protrusions and the substrate is increased. Therefore, on the basis of ensuring the peeling strength, the high-frequency transmission signal loss caused by the "skin effect" on the circuit board is reduced.

[0050] Optionally, the ratio a between the maximum width W and the maximum vertical height L of the first type of protrusion is still 1, 1.5, 2, 2.5, 3, 3.5 or 4, etc.; the ratio b between the maximum width W and the maximum vertical height L of the second type of protrusion is still 1 / 5, 1 / 4 or 1 / 3, etc.

[0051] It should be noted that the shape, size, and number ratio of the first and second type protrusions can be obtained through instrumental measurement, optionally through scanning electron microscopy (SEM), and the subsequent thickness of the metal foil can be measured by sample sectioning. In addition, the maximum width of this application refers to the maximum horizontal width.

[0052] The height and width of the protrusions described in the present application can be obtained by instrument measurement, and can optionally be obtained by directly measuring metal foil slices.

[0053] In addition, the applicant has discovered through research that for the above-mentioned second type of protrusions in the metal foil in the embodiment of the present application, due to the shape design of the second type of protrusions, the depth of the protrusions embedded in the substrate will be deeper. The longer the time the part embedded in the substrate is corroded by the etching solution, the circuit side corrosion can be prevented, thereby ensuring the yield rate of the circuit.

[0054] Furthermore, in the above embodiment, in order to ensure uniform distribution of peeling strength between the metal foil and the circuit substrate and prevent the problem of bursting, the first-class protrusions and the second-class protrusions are alternately and evenly distributed. The applicant has found through research that when 3 to 8 first-class protrusions are provided between two adjacent second-class protrusions within any sampling length on any outer contour line of the metal foil, for example, 3 first-class protrusions are provided between two adjacent second-class protrusions, 5 first-class protrusions are provided between two adjacent second-class protrusions, 7 first-class protrusions are provided between two adjacent second-class protrusions, or 8 first-class protrusions are provided between two adjacent second-class protrusions, the overall distribution uniformity of the first-class protrusions and the second-class protrusions on the metal foil is better. Therefore, when 3 to 8 first-class protrusions are provided between two adjacent second-class protrusions within any sampling length on any outer contour line of the metal foil, it can not only ensure a certain peeling strength, but also reduce the loss of high-frequency transmission signals.

[0055] It is understandable that the maximum width of the protrusions will affect the subsequent peeling effect. In an optional embodiment, in order to ensure the effectiveness of metal foil peeling, the maximum width of the first type of protrusions in this embodiment is 0.05-0.7 μm, for example, it can be 0.05 microns, 0.1 microns, 0.2 microns, 0.3 microns, 0.4 microns, 0.5 microns, 0.6 microns, 0.7 microns, etc.; the maximum width of the second type of protrusions is 0.5-3 μm, for example, it can be 0.5 microns, 0.6 microns, 0.9 microns, 1 micron, 2 microns, 3 microns, etc. Of course, the maximum width of the protrusions can be set according to actual product requirements, and no further details will be given here.

[0056] 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 15 μm, for example, 1 micron, 2 microns, 5 microns, 7 microns, 8 microns, 9 microns, 10 microns, 11 microns, 12 microns, 13 microns, 14 microns, 15 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.

[0057] 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 12 opposite to each other, selecting the second surface of the metal foil for roughening by a roughening process, forming a plurality of protrusions 121 on the surface thereof, and setting the protrusions as first-type protrusions and second-type protrusions, wherein the ratio a between the maximum width and the maximum vertical height of the first-type protrusions satisfies 1≤a≤4, and the first-type protrusions account for 50% to 90% of all the protrusions; The ratio b between the maximum width and the maximum vertical height of the second type of protrusions satisfies 1 / 5≤b≤1 / 3, and the second type of protrusions account for 10-70% of all the protrusions, and the maximum height of the first type of protrusions on the roughened surface is set to 0.05-0.7 μm; the maximum height of the second type of protrusions is set to 0.5-3 μm, and within any sampling length on any outer contour line of the metal foil, 3-8 first type protrusions are arranged between two adjacent second type protrusions, thereby forming a roughened surface, which is defined as the second surface 12 of the metal foil.

[0058] 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 as follows:

[0059] Table 1: Parameters of various metal samples

[0060] Metal foil samples A and B were fabricated into 50cm×60cm circuit board test panels. A modified semi-additive process (mSAP) was used to fabricate fine lines with a line width and line spacing of 25μm / 25μm and a line height of 25μm. The line embedding loss was measured under the following test data conditions: impedance: 85Ω (differential); length: 5 / 10 inch.

[0061] Test the peeling force between the copper foil and the substrate of this application. Test method:

[0062] After the second surface of the metal foil of the present application is pressed with PP using the Korean press 66# program, the carrier layer is peeled off, and the metal foil with the carrier layer removed is electroplated to a thickness of 15 μm, baked to remove moisture, and peeled at 90° using a 5 mm wide specimen to test the bonding strength between the copper foil and PP.

[0063] Table 2: Peel strength and embedment loss data between each metal sample and the substrate

[0064] Note: The loss in the table refers to the signal line loss.

[0065] As can be seen from the table above, by classifying the protrusions by shape and limiting their number, this application not only strengthens the bonding strength between the metal foil and the circuit substrate, but also reduces embedding loss, mitigates the skin effect of the metal foil, and improves the overall performance of the metal foil. Furthermore, in the above embodiment, the metal foil also includes a titanium roller surface or a non-Ti roller surface, thereby facilitating the subsequent deposition of the metal foil from the titanium roller surface or the non-Ti roller surface during the electroplating process.

[0066] 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 of the press and thus affecting the subsequent pressing process. Therefore, in the embodiment of the present application, the metal foil also includes an anti-oxidation layer, which is provided on the first surface and / or 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 need for pre-use cleaning. The anti-oxidation layer is made of at least one of nickel, copper, chromium, zinc, and / or an alloy of at least one of these metals.

[0067] 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 subsequent circuit fabrication. 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.

[0068] 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.

[0069] 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.

[0070] 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.

[0071] Example 2

[0072] This embodiment provides a circuit board, which includes the metal foil as described above or the copper-clad laminate as described in this application.

[0073] Example 3

[0074] This embodiment provides a copper-clad laminate, which includes the metal foil described above.

[0075] 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.

[0076] 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.

[0077] 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.

[0078] 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.

[0079] Example 4

[0080] This embodiment provides a semiconductor material, which is prepared from the metal foil described above.

[0081] Example 5

[0082] 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.

[0083] Example 6

[0084] This embodiment provides a battery, which includes the negative electrode material described above.

[0085] 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:

[0086] (1) The present application divides the roughened protrusions on the roughened surface of the metal foil into different shapes and limits their number. The first type of protrusions satisfying the ratio of maximum width to maximum vertical height of 1≤a≤4 are designed to account for 50-90% of all the roughened protrusions. The second type of protrusions satisfying the ratio of maximum width to maximum vertical height of 1 / 5≤a≤1 / 3 are designed to account for 10-70% of all the roughened protrusions. This reduces the number of spike-like particles, reduces the overall height of the particles, and increases the content of roughened protrusions with gently undulating shapes.

[0087] (2) The metal foil composed of the first type of protrusions of a specific shape and the second type of protrusions of a specific shape reduces the depth of the roughened protrusions embedded in the substrate, but increases the contact area between the roughened protrusions and the substrate. Therefore, on the basis of ensuring the peeling degree, the high-frequency transmission signal loss caused by the "skin effect" on the circuit board is reduced, the quality of the metal foil is effectively improved, and the electrical performance of the circuit board is guaranteed;

[0088] (3) The shape design of the second type of protrusion will make it embedded deeper in the substrate. The longer the time the part embedded in the substrate is corroded by the etching solution, the more likely it is to cause side corrosion of the circuit and ensure the yield rate of the circuit.

[0089] 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, and a plurality of protrusions are provided on the second surface, and the protrusions include a first type of protrusion and a second type of protrusion; For the first type of protrusion, the ratio a between the maximum width and the maximum vertical height satisfies 1≤a≤4, and the first type of protrusion accounts for 50-90% of all the protrusions; For the second type of protrusion, the ratio b between the maximum width and the maximum vertical height satisfies 1 / 5≤b≤1 / 3, and the second type of protrusion accounts for 10-70% of all the protrusions.

2. The metal foil according to claim 1, characterized in that, Within any sampling length on any outer contour line of the metal foil, 3-8 of the first type of protrusions are provided between adjacent two of the second type of protrusions.

3. The metal foil according to claim 1, characterized in that, The maximum height of the first type of protrusion is 0.05-0.7 μm; the maximum height of the second type of protrusion is 0.5-3 μm.

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

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

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

7. The metal foil according to claim 1, characterized in that, The metal foil further includes a release layer, and the release layer is provided on the first surface.

8. The metal foil according to claim 1, characterized in that, 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.

9. The metal foil according to claim 1, characterized in that, 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.

10. A copper-clad laminate, characterized in that, It includes the metal foil according to any one of claims 1-9.

11. The copper-clad laminate according to claim 10, 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.

12. The copper-clad laminate according to claim 11, wherein 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, polyether ether ketone, polyphenylene ether, polytetrafluoroethylene, liquid crystal polymer, polyoxalylurea, epoxy glass cloth, BT resin.

13. The copper-clad laminate according to claim 10, 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.

14. The copper-clad laminate according to claim 13, 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.

15. A circuit board, characterized in that, The circuit board includes the metal foil according to any one of claims 1-9 or the copper-clad laminate according to any one of claims 10-14.

16. A semiconductor material, characterized in that, The semiconductor material is prepared from the metal foil according to any one of claims 1-9.

17. 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 1-9 and an electrode active material coated on the surface of the metal foil.

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

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