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; the average grain size of the metal within an H thickness range of the metal foil is 0.1-0.8 μm, the H thickness range being the positions at 0.5-2.5 μm from the first surface in the direction of the second surface. 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, a browned copper foil with an L value of 20-35 is obtained by designing the grain size of the metal foil surface; when laser drilling is performed on the copper foil, the obtained holes have smooth edges, the holes have an ideal shape, and trapezoidal or inverted trapezoidal holes do not occur, thus ensuring laser drilling quality and efficiency.

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 202311805430.6 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 202410148759.8 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. High-precision electronic metal foil or double-sided roughened electrolytic metal foil is usually used for the inner layers of high-density fine-circuit PCBs or multi-layer complex PCBs. However, in the SAP or MSAP process, laser drilling of multi-layer boards may result in metal sputtering residues at the edges of the holes, burrs on the holes, or the holes may not achieve the ideal shape, but may be trapezoidal or inverted trapezoidal, thus affecting the quality of the circuit board.

[0006] It can be seen that how to design metal foil to ensure the quality and efficiency of laser drilling 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. By designing the grain size of the metal foil, a brown copper foil with an L value of 20 to 35 is obtained. When the copper foil is laser-drilled, the edges of the holes obtained are smooth and the shape of the holes is relatively ideal. There will be no trapezoidal or inverted trapezoidal holes, thereby ensuring the quality and efficiency of the laser drilling.

[0009] 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 the average grain size of the metal within the thickness range H of the metal foil is 0.1 to 0.8 μm, and the thickness range H is 0.5 to 2.5 μm deep from the first surface to the second surface.

[0010] As one of the optional solutions, the average grain size of the metal within the thickness range H of the metal foil is 0.1 to 0.4 μm, and the thickness range H is 1 to 1.5 μm deep from the first surface to the second surface.

[0011] As one optional solution, the color value of the first surface after browning satisfies: L value is 20-35.

[0012] Optionally, the color value of the first surface further satisfies: the a value is 7-15 and the b value is 7-15.

[0013] As an optional solution, the second surface is a non-flat surface.

[0014] As an optional solution, the thickness of the metal foil is 0.5 to 50 μm.

[0015] 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.

[0016] As an optional solution, the metal foil further includes a peeling layer, and the peeling layer is provided on the first surface.

[0017] 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.

[0018] 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, the metal material is an alloy formed by any 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.

[0019] Another embodiment of the present application provides a copper-clad laminate, which includes the metal foil as described above.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] Another embodiment of the present application provides a semiconductor material, which is prepared from the metal foil as described above.

[0026] 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.

[0027] Another embodiment of the present application provides a battery, which includes the negative electrode material as described above.

[0028] Compared with the prior art, the embodiments of the present application have the following advantages:

[0029] (1) The present application improves the average grain size of a certain thickness of metal foil. Since the metal foil needs to be browned in the circuit board manufacturing process, the surface of the metal foil is brown. Therefore, the metal grain size has a great influence on the browning process. If the size is too large, the browning solution will erode too slowly, and the browning film formed will be too light in color. If the size is too small, the browning solution will erode too quickly, and the browning film formed will be too dark in color. The thickness of metal grains of appropriate size also affects the effect of the browning process. If the thickness is too light, the browning process will end prematurely and the browning film will not be formed. If the thickness is too dark, the browning treatment time will be extended, resulting in the browning touch being too dark in color and the inability to form an ideal browning film, which will result in the inability to obtain an ideal hole in the subsequent laser drilling process.

[0030] (2) The present application also studies the color of the metal foil surface after browning. Since laser drilling is required in the circuit board manufacturing process, the brown color depth of the metal foil surface will affect the energy absorbed by the laser. Dark colors absorb high energy, while light colors absorb low energy. If the color is too high, the aperture of the holes formed by the copper layer and the substrate will be different, resulting in the aperture of the substrate layer being larger than the aperture of the copper layer; if the color is too low, burrs will form on the edge of the hole, affecting the quality of laser drilling. Therefore, the embodiment of the present application designs the brown color depth of the metal foil surface. When laser drilling is performed, the edge of the hole obtained is smooth and the shape of the hole is relatively ideal. There will be no trapezoidal or inverted trapezoidal holes, thereby ensuring the quality and efficiency of laser drilling.

[0031] (2) In the present application, the brown color depth of the metal foil surface is adjusted so that the L value of the first surface of the metal foil based on the L*a*b* color difference system is 20 to 35; optionally, the a value of the L*a*b* color difference system is 7 to 15, and the b value is 7 to 15. When the metal foil is used for laser drilling using the SAP or MSAP process, the edges of the obtained holes are smooth, the metal foil has less overhang, and has an ideal shape. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] FIG1 is a schematic diagram of a metal foil in one embodiment of the present application;

[0033] FIG2 is a schematic diagram of a metal foil in one embodiment of the present application;

[0034] FIG3 is a schematic diagram of a metal foil in one embodiment of the present application;

[0035] Reference numerals:

[0036] Among them, 1. metal foil; 11. second surface; 111. metal grains; 2. anti-oxidation layer; 3. peeling layer; 4. carrier layer. DETAILED DESCRIPTION

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] Example 1

[0042] Please refer to FIG. 1 , which conceptually shows a schematic structural diagram of a metal foil provided in an embodiment of the present application. The metal foil includes a first surface and a second surface 11 that are opposite to each other.

[0043] In the embodiments of the present application, in order to avoid the residual metal sputtering marks and burr formation on the hole edges during laser drilling of multilayer boards in the SAP or MSAP processes, or the phenomenon of the drilled holes not achieving the ideal trapezoidal or inverted trapezoidal shape, the applicant, through extensive experimental analysis, found that this problem is caused by improper processing of the browning process, which is affected by the metal grain size. The metal grain size has a significant impact on the browning process. If the size is too large, the browning solution will erode too slowly, resulting in a browning film that is too light in color. If the size is too small, the browning solution will erode too quickly, resulting in a browning film that is too dark in color. The thickness of the appropriately sized metal grains also affects the effectiveness of the browning process. If the thickness is too shallow, the browning process will end prematurely and the browning film will not form. If the thickness is too thick, the browning process will be prolonged, resulting in a dark browning color, which will not form the ideal browning film and will result in an unsatisfactory browning depth on the metal foil surface. The browning depth of the metal foil surface also affects the energy absorbed by the laser: darker colors absorb more energy, while lighter colors absorb less energy. If the color is too high, the aperture of the holes formed by the copper layer and the substrate will be different, resulting in the aperture of the substrate layer being larger than that of the copper layer; if the color is too low, burrs will form on the edge of the hole, affecting the quality of laser drilling.

[0044] Therefore, the embodiment of the present application improves the average grain size within a certain thickness of the metal foil while also limiting the color of the metal foil surface after browning, so that when laser drilling is performed, the edges of the holes obtained are smooth and the shape of the holes is relatively ideal, and there will be no trapezoidal or inverted trapezoidal holes, thereby ensuring the quality and efficiency of laser drilling.

[0045] Specifically, in an embodiment of the present application, the metal foil includes a first surface and a second surface relative to each other, the average grain size of the metal within the thickness range H of the metal foil is 0.1 to 0.8 μm, and the thickness range H is 0.5 to 2.5 μm deep from the first surface to the second surface.

[0046] During the browning process of circuit board manufacturing, the metal foil will be etched away by the solution to a certain thickness due to the browning micro-etching process. In order to improve the efficiency of the browning micro-etching and form an ideal browning film, the present application improves the size of the metal grains in the metal foil portion to be etched. Specifically, the average metal grain size within the thickness range of the metal foil H is 0.1 to 0.8 μm, and the thickness range H is the thickness range H from the first surface. Pointing to a position 0.5 to 2.5 μm deep in the direction of the second surface, for example, the grain size can be 0.1 μm, 0.2 μm, 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.7 μm or 0.8 μm, etc.; the H thickness is 0.5 μm, 0.8 μm, 1.0 μm, 1.2 μm, 1.4 μm, 1.6 μm, 1.8 μm, 2.0 μm, 2.2 μm, 2.4 μm or 2.5 μm, etc.

[0047] Of course, the above average grain size can be set according to the actual product requirements, and no further details will be given here. Browning the metal foil is not only for laser drilling, but also for roughening it to obtain a certain degree of roughness and improve the bonding strength between the metal foil and the circuit substrate. During the browning process, the etching solution will corrode the surface of the metal foil. During this process, the browning solution will corrode the surface of the metal foil while forming a browning film. If the metal grains are too large, it will not only affect the corrosion speed of the solution, but also have a certain impact on the formation process of the browning film. The larger the grains, the more difficult it is to be corroded by the solution, and the more difficult it is to form a browning film. The smaller the grains, the easier it is to be over-corroded, and the darker the color of the formed browning film. This will cause the color value L value of the metal foil surface to be smaller, thereby affecting the effect of subsequent laser drilling.

[0048] The present application also found that setting the average grain size of the metal grains in the thickness range of 0.5 to 2.5 μm from the first surface to the second surface of the metal foil to 0.1 to 0.8 μm can solve the problem of uneven surface roughness of the metal foil and uneven thickness of the metal foil on the board after browning micro-etching. The uneven roughness of the metal foil will lead to uneven bonding between it and the substrate, causing board explosion, and the uneven thickness of the metal foil will lead to inconsistent thickness of the prepared circuit, causing signal transmission distortion and other problems. This is because when the metal foil of the present application comes into contact with the micro-etching solution, the metal grain size in different areas tends to be consistent and the etching speed is the same. When the solution further corrodes to a certain thickness, the grain size within this thickness range tends to be consistent, and the etching speed of the solution is also consistent. Therefore, the roughness obtained by corrosion is also consistent, the thickness of the metal bitten is consistent, and the thickness of the remaining metal is also consistent. Therefore, the metal thickness of the board surface is uniform, the speed of forming the browning film is also consistent, and the browning color value obtained is also consistent.

[0049] It should be noted that the average grain size of the above-mentioned metal foil can be measured by average distribution statistics using EBSD (electron backscatter diffraction), the grain size in the thickness direction can be measured by EBSD (electron backscatter diffraction), and the thickness can be obtained by measuring the cross-sectional image of the metal foil using a scanning electron microscope (SEM).

[0050] Furthermore, it was found that when the average grain size of the metal within the thickness range H of the metal foil is 0.1 to 0.4 μm, and the thickness range H is 1 to 1.5 μm deep from the first surface to the second surface, a more stable effect can be obtained.

[0051] Specifically, in an embodiment of the present application, the first surface is based on the L*a*b* color difference system, and its L value is 20 to 35; optionally, its a value is 7 to 15, and its b value is 7 to 15. For example, the L value of the first surface can be 20, 21, 25, 26, 28, 30, 35, the a value of the first surface can be 7, 8, 9, 12, 14, 15, and the b value of the first surface can be 7, 8, 9, 12, 14, 15. When the metal foil is used for laser drilling using the SAP or MSAP process, the above phenomenon will not occur, and the edges of the obtained holes are smooth, no metal hanging edges will be generated, and they have an ideal shape.

[0052] Illustratively, in one embodiment, the metal foil of the present application can be obtained by the following method: forming a metal foil on a titanium roller by chemical deposition (for example, electroplating), and making the average grain size of the metal in the range of 0.1 to 0.8 μm, and the thickness of the metal in the range of 0.5 to 2.5 μm, and then depositing a layer of metal on the aforementioned metal again by chemical deposition (for example, electroplating), and adjusting the average grain size of the metal to the required size according to actual needs, which in this embodiment can be in the range of 0.8<a2≤4 μm, and finally making the overall thickness of the metal foil 5 μm; through the browning process, the color value of the first surface satisfies: L value is 20 to 35; optionally, a value is 7 to 15 and b value is 7 to 15.

[0053] A represents the metal foil product of the embodiment of the present application, and five metal foil samples A1, A2, A3, A4, and A5 are randomly selected for comparison with comparative example B. The parameters of each metal sample are as follows:

[0054] Table 1: Parameters of various metal samples

[0055] Note: In this example, the average grain size of the metal is obtained by taking an arbitrary length on the cross-sectional view of the metal foil and measuring the average grain size (area-weighted mean) of the thickness H within the sampling length by EBSD or SEM, that is, the average grain size of the metal in the overall distribution of the thickness H.

[0056] Metal foil samples A and B were used to prepare multi-layer circuit boards and laser drilled. The edges of the holes were observed to see if there were any traces of metal sputtering residue, any burrs formed on the edges of the holes, whether the drilled holes were trapezoidal or inverted trapezoidal, and whether there were any metal overhangs on the holes in the substrate.

[0057] Measure the roughness of metal samples and the thickness of metal foil. Roughness is tested using a roughness meter: Cut a carrier copper sample and select three equally spaced points on the left, center, and right sides of the browned metal foil surface. Use a roughness meter to measure the Ra value. If the difference between the measured values ​​is ≤10%, it is considered uniform; if it is greater than 10%, it is considered uneven. The thickness of the metal foil is measured using the following method: The thickness of the metal foil is measured through a SEM image of the cross section. The thickness of the three equally spaced points is selected. If the difference between the measured values ​​is ≤5%, it is considered uniform; if it is greater than 5%, it is considered uneven. The test results are shown in the table below:

[0058] Table 2: Punching results of various metal samples

[0059] As can be seen from the above table, this application obtains the ideal metal foil color value L value by adjusting the distribution of metal foil grain size and thickness ratio, and avoids the occurrence of metal sputtering residues on the hole edge, burr formation on the hole edge, and no metal hanging edge on the substrate hole when the metal foil is laser punched in a multilayer board. This improves the shape of the hole, ensures the quality and efficiency of laser drilling, and also ensures the uniformity of the metal foil surface roughness and the uniformity of the metal foil surface thickness after browning.

[0060] 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 or / and the second surface. The anti-oxidation layer is made of at least one of metals such as nickel, copper, zinc and / or an alloy of at least one of them. By designing an anti-oxidation layer, the outer surface of the metal foil is not easily contaminated by moisture, dust and other objects in the air, and can maintain a relatively dry and clean surface state. At the same time, it is not easily oxidized, which can better protect the metal foil. It can also simplify the environmental requirements for the transportation and storage of the metal foil and reduce the cleaning process before the application of the metal foil.

[0061] 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 is understandable that there is no particular limitation on the types of the above solvents, and conventional release agent solvents in the art, such as butanone, may be selected, which does not constitute a limitation on the present application.

[0062] Optionally, when the release layer is made of a metallic material, the thickness of the release layer is 2 to 100 nm; or, when the release layer is made of a non-metallic material, the thickness of the release layer is less than or equal to 1 μm. The specific thickness of the release layer can be set according to actual use requirements and is not further described here.

[0063] In an embodiment of the present application, the metal foil further comprises a carrier layer, which is disposed above 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 copper, aluminum, zinc, nickel, chromium, iron, silver, gold, and the like.

[0064] In an embodiment of the present application, the metal material of the metal foil may be a single metal material, which may be 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 may also be an alloy, for example, an alloy formed by any 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.

[0065] Example 2

[0066] This embodiment provides a circuit board, which includes the metal foil as described above or the copper-clad laminate of the present application.

[0067] Example 3

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

[0069] 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.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] Example 4

[0074] This embodiment provides a semiconductor material, which is prepared from the metal foil described above.

[0075] Example 5

[0076] 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.

[0077] Example 6

[0078] This embodiment provides a battery, which includes the negative electrode material described above.

[0079] 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:

[0080] (1) The present application improves the average grain size of a certain thickness of metal foil. Since the metal foil needs to be browned in the circuit board manufacturing process, the surface of the metal foil is brown. Therefore, the metal grain size has a great influence on the browning process. If the size is too large, the browning solution will erode too slowly, and the browning film formed will be too light in color. If the size is too small, the browning solution will erode too quickly, and the browning film formed will be too dark in color. The thickness of the metal grains of appropriate size also affects the effect of the browning process. If the thickness is too shallow, the browning process will end prematurely and the browning film will not be formed. If the thickness is too deep, the browning treatment time will be extended, resulting in the browning film being too dark in color and unable to form an ideal browning film, resulting in the inability to obtain an ideal hole in the subsequent laser drilling process. Therefore, the present application provides a metal foil, which includes a first surface and a second surface relative to each other. The average metal grain size within the thickness range H of the metal foil is 0.1 to 0.8 μm, and the thickness range H is 0.5 to 2.5 μm deep from the first surface to the second surface. By adjusting the metal grain size within a certain thickness of the metal foil, an ideal browning film can be obtained in the browning process.

[0081] (2) The present application also studies the color of the metal foil surface after browning. Since laser drilling is required in the circuit board manufacturing process, the brown color depth of the metal foil surface will affect the energy absorbed by the laser. Dark colors absorb high energy, while light colors absorb low energy. If the color is too high, the aperture of the holes formed by the copper layer and the substrate will be different, resulting in the aperture of the substrate layer being larger than the aperture of the copper layer; if the color is too low, burrs will form on the edge of the hole, affecting the quality of laser drilling. Therefore, the embodiment of the present application designs the brown color depth of the metal foil surface, so that when laser drilling is performed, the edge of the hole obtained is smooth, the shape of the hole is relatively ideal, and there will be no trapezoidal or inverted trapezoidal holes, thereby ensuring the quality and efficiency of laser drilling;

[0082] (2) In the present application, the brown color depth of the metal foil surface is adjusted so that the L value of the first surface of the metal foil based on the L*a*b* color difference system is 20 to 35; optionally, the a value of the L*a*b* color difference system is 7 to 15, and the b value is 7 to 15. When the metal foil is used for laser drilling using the SAP or MSAP process, the edges of the obtained holes are smooth, the metal foil has less overhang, and has an ideal shape.

[0083] 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. The average grain size of the metal within the H thickness range of the metal foil is 0.1 - 0.8 μm, and the H thickness range is the position 0.5 - 2.5 μm deep in the direction from the first surface towards the second surface.

2. The metal foil according to claim 1, characterized in that, The average grain size of the metal within the H thickness range of the metal foil is 0.1 - 0.4 μm, and the H thickness range is the position 1 - 1.5 μm deep in the direction from the first surface towards the second surface.

3. The metal foil according to claim 2, characterized in that, The color value of the first surface after browning satisfies: the L value is 20 - 35.

4. The metal foil according to claim 3, wherein, The second surface is an uneven surface.

5. The metal foil according to any one of claims 1 to 4, characterized in that, The thickness of the metal foil is 0.5 - 50 μm.

6. The metal foil according to claim 5, 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, wherein 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 8, 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 any 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, The copper-clad laminate 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 surface 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, and 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 the surface 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, and 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.

Images