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

Abstract

This invention discloses a metal foil, a circuit board, a copper-clad laminate, a semiconductor, a negative electrode material, and a battery. The metal foil includes a roughened surface, and the arithmetic mean roughness Ra of the roughened surface and the water droplet angle Y of the roughened surface satisfy the following functional relationship: Y = -6672.5 × Ra 2 +2761.3×Ra-147.36, Ra>0, Y>90°, and the correlation coefficient R of the stated function relationship. 2 The value is 0.9973. By employing the technical means of this invention, the relationship between the roughness of the roughened surface of the metal foil and the water droplet angle is optimized, so that both the water droplet angle and roughness of the roughened surface are within an optimal range, effectively improving the hydrophobicity of the roughened surface of the metal foil and improving the quality of the metal foil product.

Description

Technical Field

[0001] This invention relates to the field of metal foil technology, and more particularly to a metal foil, circuit board, copper-clad laminate, semiconductor, negative electrode material, and battery. Background Technology

[0002] Metal foil is an important material widely used in the electronics industry. It is one of the key materials for products such as flexible copper-clad laminates and printed circuit boards. In printed circuit boards, metal foil plays a vital role in conducting circuits and interconnecting components, and is known as the "neural network" for signal and power transmission and communication in electronic products. At the same time, metal foil is also an important raw material in chip packaging and new energy batteries.

[0003] The rapid development of microelectronics and new energy batteries has placed higher demands on the various physical properties of metal foils, such as hydrophilicity / hydrophobicity, high strength, ductility, and low surface roughness. Due to the different processing techniques and practical needs of different sides of the metal foil, the specific requirements for its physical properties are related to the specific application scenario. For example, when a metal foil is used in a scenario requiring hydrophobicity, the surface of the foil must have a certain degree of hydrophobicity to effectively prevent the adsorption of moisture and other contaminants from the air, thus avoiding oxidation, or to enhance adhesion when pressed with non-hydrophilic materials, such as when one side of the metal foil is bonded to a circuit board substrate using a specific adhesive. However, current metal foils still struggle to meet these requirements. Therefore, providing a metal foil that can meet these performance requirements is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0004] The purpose of this invention is to provide a metal foil, circuit board, copper-clad laminate, semiconductor, negative electrode material, and battery. By optimizing the relationship between the roughness of the roughened surface of the metal foil and the water droplet angle, the hydrophobicity of the roughened surface of the metal foil is effectively improved, thereby improving the quality of the metal foil product.

[0005] To achieve the above objectives, embodiments of the present invention provide a metal foil including a roughened surface, wherein the arithmetic mean roughness Ra of the roughened surface and the water droplet angle Y of the roughened surface satisfy the following functional relationship:

[0006] Y = -6672.5 × Ra 2 +2761.3×Ra-147.36, Ra>0, Y>90°, and the correlation coefficient R of the stated function relationship. 2 It is 0.9973.

[0007] As an improvement to the above scheme, the water droplet angle Y of the roughened surface is 120° to 139°.

[0008] As an improvement to the above scheme, the arithmetic mean roughness Ra of the roughened surface is 0.16 to 0.3 μm.

[0009] As an improvement to the above scheme, the roughness Rz of the roughened surface is less than or equal to 2 μm.

[0010] As an improvement to the above scheme, the water droplet angle X on the other side opposite to the roughened surface is less than 60°.

[0011] As an improvement to the above solution, the metal foil includes a conductive layer, a release layer, and a carrier layer stacked sequentially, with one side of the conductive layer being the roughened surface; the release layer and the carrier layer are disposed on the other side of the conductive layer opposite to the roughened surface.

[0012] As an improvement to the above scheme, the material of the conductive layer includes at least one of the following metallic elements: copper, aluminum, zinc, nickel, gold, silver, chromium, and cobalt, and / or an alloy of at least one of them.

[0013] As an improvement to the above scheme, the thickness of the conductive layer is 1 to 6 μm.

[0014] As an improvement to the above scheme, the material of the carrier layer includes at least one of the following metallic elements: copper, aluminum, zinc, nickel, chromium, iron, silver, and gold, in which case the thickness of the carrier layer is 5 to 50 μm; or, the material of the carrier layer is an organic thin film, in which case the thickness of the carrier layer is 10 to 100 μm.

[0015] As an improvement to the above scheme, the material of the release layer is a metallic material, and the thickness of the release layer is 2 to 100 nm; or, the material of the release layer is a non-metallic material, and the thickness of the release layer is less than or equal to 1 μm.

[0016] This invention also provides a circuit board, including a circuit board substrate and a metal foil as described in any of the above embodiments; the roughened surface of the metal foil is pressed against the circuit board substrate.

[0017] This invention also provides a copper-clad laminate, the copper-clad laminate comprising the metal foil described in any of the preceding embodiments.

[0018] This invention also provides a semiconductor material, which includes a metal foil as described in any of the preceding embodiments.

[0019] This invention also provides a negative electrode material for use in batteries, the negative electrode material comprising a metal foil as described in any of the preceding embodiments.

[0020] The present invention also provides a battery, wherein the negative electrode material of the battery comprises a metal foil as described in any of the preceding embodiments.

[0021] Compared with the prior art, the metal foil disclosed in this invention includes a roughened surface, and the arithmetic mean roughness Ra of the roughened surface satisfies the following functional relationship with the water droplet angle Y: Y = -6672.5 × Ra 2 The parameters +2761.3×Ra-147.36, Ra>0, and Y>90° give the roughened surface of the metal foil good hydrophobicity. When the metal foil is applied to a printed circuit board, it effectively prevents contaminants such as moisture in the air from adsorbing onto the roughened surface. This effectively solves various problems caused by oxidation of the roughened surface of the metal foil due to the adsorption of contaminants such as moisture in the air, which can lead to decreased circuit conductivity or even insulation. It also reduces oxidation and contamination of the metal foil surface, lowers the environmental requirements for the transportation and storage of the metal foil, and reduces or simplifies the cleaning process before application (existing metal foils require separate cleaning before use). Meanwhile, by optimizing the hydrophobicity of the roughened surface, problems such as poor bonding and loose adhesion between the roughened surface and the resin adhesive during the subsequent lamination process of the metal foil and the circuit board substrate can be avoided, leading to reduced adhesion to the substrate. This ensures excellent bonding between the metal foil and the circuit board substrate, as well as sufficient spreading and adhesion with the adhesive, reducing the possibility of blistering and board bursting, increasing the yield rate of products, and saving production costs. Furthermore, this embodiment of the invention further optimizes the water droplet angle Y of the roughened surface to 120°~139°, and / or the arithmetic mean roughness Ra of the roughened surface to 0.16~0.3μm, so that the water droplet angle and roughness of the roughened surface are within an optimal range, thereby giving the roughened surface excellent hydrophobicity, adhesion, and peel strength. Attached Figure Description

[0022] Figure 1 This is a top-view electron microscope image of the first type of metal foil provided in the embodiments of the present invention;

[0023] Figure 2 This is a schematic diagram of the structure of the first type of metal foil provided in an embodiment of the present invention;

[0024] Figure 3 This is a schematic diagram of the structure of the second type of metal foil provided in an embodiment of the present invention;

[0025] Figure 4 This is a schematic diagram of the structure of the third type of metal foil provided in the embodiments of the present invention;

[0026] Figure 5 This is a schematic diagram of the structure of the fourth type of metal foil provided in the embodiments of the present invention;

[0027] Figure 6This is a schematic diagram of the structure of the fifth type of metal foil provided in the embodiments of the present invention;

[0028] Figure 7 This is a schematic diagram of the structure of the sixth type of metal foil provided in the embodiments of the present invention;

[0029] Figure 8 This is a schematic diagram of the structure of the seventh type of metal foil provided in the embodiments of the present invention;

[0030] Figure 9 This is a schematic diagram of the structure of the eighth type of metal foil provided in the embodiments of the present invention;

[0031] Figure 10 This is a schematic diagram of the structure of the ninth type of metal foil provided in the embodiments of the present invention;

[0032] Figure 11 This is a schematic diagram of the structure of the tenth type of metal foil provided in this embodiment of the invention;

[0033] Figure 12 This is a schematic diagram of the structure of the eleventh type of metal foil provided in the embodiments of the present invention;

[0034] Figure 13 This is a schematic diagram of the structure of a circuit board provided in an embodiment of the present invention;

[0035] Among them, 1. roughened surface; 11. roughened particles; 2. conductive layer; 3. carrier layer; 31. first filler particles; 4. release layer; 41. second filler particles; 5. adhesive layer; 6. first anti-oxidation layer; 7. second anti-oxidation layer; 8. resin layer; 9. circuit board substrate. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] In the description of the specification and claims, it should be understood that the terms "upper", "lower", "left", "right", "front", "rear", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the embodiments of the present invention, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the embodiments of the present invention.

[0038] Furthermore, the terms "first," "second," etc., used in the specification and claims are used only to distinguish the description of the same technical features and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated, nor necessarily the order of description or chronological sequence. Where appropriate, the terms are interchangeable. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature.

[0039] Example 1

[0040] See Figure 1 and Figure 2 , Figure 1 This is a top-view electron microscope image of the first type of metal foil provided in the embodiments of the present invention; Figure 2 This is a schematic diagram of the structure of the first type of metal foil provided in this embodiment of the invention. This embodiment of the invention provides a metal foil, including a roughened surface 1. Specifically, the surface of the metal foil subjected to the roughening process is the roughened surface. The roughening process includes setting a plurality of roughening particles 11 on the roughened surface 1. The roughening particles 11 refer to protrusions formed on the corresponding surface of the metal foil subjected to the roughening process.

[0041] It should be noted that in practical applications, the metal foil can be used in various fields, such as circuit boards and batteries. During application, the metal foil can be pressed against the application carrier through its roughened surface. In one optional embodiment, when the metal foil is used in the circuit board field, it is thermally bonded to the circuit board substrate through the roughened surface. In another optional embodiment, when the metal foil is used in the battery field, it serves as the negative electrode material of the battery, and is thermally bonded to the negative electrode active material through the roughened surface.

[0042] It should be noted that, Figure 1 and Figure 2 The shape of the roughened particles 11 described herein is merely exemplary. Due to differences in processing methods and parameters, the roughened particles 11 can also be other regular or irregular protruding shapes such as clusters, ice formations, stalactites, or dendrites. Furthermore, the roughened particles 11 in this embodiment are not limited to the shapes shown in the figures and described above. Any roughened particles 11 that provide surface roughness for the metal foil are within the scope of protection of this invention. In specific implementations, a metal foil material layer can be formed first, and then the roughened particles 11 can be formed on the material layer through other processes. Of course, the metal foil material layer and the roughened particles 11 can also be an integral structure formed through a one-time molding process. It should be noted that the material of the roughened particles 11 can be the same as or different from the material of the metal foil; this is not limited here.

[0043] Of course, the roughening process also includes setting the surface of the metal foil as an undulating, non-flat surface, or setting several tiny bumps and depressions on the surface of the metal foil, or a combination of at least two of the above three implementation methods, none of which constitute a limitation of the present invention.

[0044] The arithmetic mean roughness Ra of the roughened surface of the metal foil of the present invention satisfies the following functional relationship with the water droplet angle Y of the roughened surface: Y = -6672.5 × Ra 2 +2761.3×Ra-147.36, Ra>0, Y>90°, and the correlation coefficient R of the stated function relationship. 2 It is 0.9973.

[0045] It should be noted that the arithmetic mean roughness Ra is specifically the arithmetic mean of the absolute values ​​of the profile ordinate Z(x) within a sampling length. The ordinate Z(x) refers to the distance from each point on the profile to the profile centerline. The arithmetic mean roughness Ra is used to evaluate the arithmetic mean deviation of the surface profile, and it can fully reflect the height characteristics of the surface micro-geometry.

[0046] Since the hydrophobic properties exhibited by the roughened surface 1 are related to the size of the water droplet angle γ and the roughness of the roughened surface 1, generally, the larger the water droplet angle γ, the stronger the hydrophobicity, and the smaller the water droplet angle γ, the weaker the hydrophobicity; similarly, the larger the roughness, the stronger the hydrophobicity, and the smaller the roughness, the weaker the hydrophobicity. In this embodiment of the invention, by fitting the functional relationship between the arithmetic roughness Ra and the water droplet angle γ, the arithmetic mean roughness Ra of the roughened surface 1 and the water droplet angle γ of the roughened surface 1 have a certain functional correlation. When the water droplet angle γ and the arithmetic mean roughness Ra of the roughened surface 1 of the metal foil simultaneously satisfy the above functional relationship, the roughened surface 1 can simultaneously have a reasonable roughness range and a reasonable water droplet angle range, resulting in better hydrophobic properties exhibited by the roughened surface 1, which meets the hydrophobicity requirements for the roughened surface of the metal foil. Furthermore, the correlation coefficient R of the functional relationship... 2 The correlation coefficient is 0.9973, which is close to 1, indicating that the regression fit is good and the arithmetic mean roughness Ra has a strong functional relationship with the teardrop angle Y.

[0047] By employing the technical means of this invention, the roughened surface of the metal foil exhibits good hydrophobicity, reducing its surface energy. This effectively prevents moisture and other contaminants from adsorbing onto the roughened surface when the metal foil is applied in applications requiring hydrophobicity, such as printed circuit boards. This effectively solves various problems caused by oxidation of the roughened surface due to the adsorption of moisture and other contaminants, which can lead to decreased circuit conductivity or even insulation. It also reduces oxidation and contamination of the metal foil surface, lowers the environmental requirements for transportation and storage, and simplifies the cleaning process before application. Furthermore, by optimizing the hydrophobicity of the roughened surface, it avoids poor bonding and loose adhesion between the roughened surface and the resin adhesive during the subsequent lamination process between the metal foil and the circuit board substrate. This ensures excellent bonding between the metal foil and the circuit board substrate, as well as sufficient adhesion to the adhesive, reducing the possibility of blistering and board bursting, increasing the product yield, and saving production costs.

[0048] In a preferred embodiment, the water droplet angle Y of the roughened surface is 120° to 139°.

[0049] In this embodiment of the invention, based on the fact that the water droplet angle Y and the arithmetic mean roughness Ra of the roughened surface of the metal foil satisfy the above functional relationship, the numerical range of the water droplet angle Y of the roughened surface is further optimized. The water droplet angle Y of the roughened surface is between 120° and 139°, for example, it can be 120°, 121°, 122°, 123°, 124°, 125°, 126°, 127°, 128°, 129°, 130°, 131°, 132°, 133°, 134°, 135°, 136°, 137°, 138° or 139°. Of course, the specific value of the water droplet angle Y of the roughened surface can be set according to the actual usage requirements, which will not be elaborated further here.

[0050] By employing the technical means of this invention, the roughened surface possesses excellent hydrophobicity, effectively preventing the adsorption of moisture and other contaminants from the air onto the roughened surface, thus avoiding oxidation and contamination of the metal foil surface. Simultaneously, the roughened surface of the metal foil has a reasonable roughness, effectively ensuring its adhesive performance and guaranteeing excellent adhesion between the metal foil and application carriers such as circuit board substrates. This meets the appropriate peel strength requirements during lamination with application carriers such as circuit board substrates, comprehensively improving the quality of the metal foil product.

[0051] In a preferred embodiment, the arithmetic mean roughness Ra of the roughened surface is 0.16 to 0.3 μm.

[0052] In this embodiment of the invention, based on the fact that the teardrop angle Y and the arithmetic mean roughness Ra of the roughened surface of the metal foil satisfy the above functional relationship, the numerical range of the arithmetic mean roughness Ra of the roughened surface is further optimized. The arithmetic mean roughness Ra of the roughened surface is between 0.16 and 0.3 μm, for example, it can be 0.16 μm, 0.17 μm, 0.18 μm, 0.19 μm, 0.20 μm, 0.21 μm, 0.22 μm, 0.23 μm, 0.24 μm, 0.25 μm, 0.26 μm, 0.27 μm, 0.28 μm, 0.29 μm or 0.3 μm. Of course, the specific value of the arithmetic mean roughness Ra of the roughened surface can be set according to the actual usage requirements, which will not be elaborated further here.

[0053] By employing the technical means of this invention, the roughness of the roughened surface is kept within an optimal range, improving its adhesive performance and ensuring excellent adhesion between the metal foil and application carriers such as circuit board substrates. This meets the requirements for appropriate peel strength during pressing with application carriers such as circuit board substrates. Simultaneously, the roughened surface, satisfying this arithmetic mean roughness range and the aforementioned functional relationship, also has a water droplet angle γ within a reasonable range, thus exhibiting excellent hydrophobicity. This reduces the surface energy of the roughened surface of the metal foil, effectively preventing the adsorption of pollutants such as moisture in the air onto the roughened surface, avoiding oxidation and contamination of the metal foil surface. It also effectively simplifies environmental requirements for transportation and storage, and reduces the cleaning process before copper foil application.

[0054] In a preferred embodiment, based on any of the above embodiments, the roughness Rz of the roughened surface is less than or equal to 2 μm. Preferably, the roughness Rz of the roughened surface is less than or equal to 1.8 μm.

[0055] For example, the roughness Rz of the roughened surface can be 1μm, 1.1μm, 1.2μm, 1.3μm, 1.4μm, 1.6μm or 1.8μm, etc. Of course, it can also be set to other values ​​less than or equal to 1.8μm according to the actual situation, which will not be elaborated here.

[0056] It should be noted that the roughness Rz is the sum of the average of the n largest profile peak heights and the average of the n largest profile valley depths within the sampling length, where n ≥ 1; preferably, n = 5. The roughness Rz can fully reflect the peak height of the profile.

[0057] In this embodiment of the invention, based on the fact that the water droplet angle Y and the arithmetic mean roughness Ra of the roughened surface of the metal foil satisfy the above functional relationship, the numerical range of the roughness Rz of the roughened surface is further optimized. The roughness Rz of the roughened surface is ≤2μm. The roughness characteristics of the roughened surface are characterized by the combination of the arithmetic mean roughness Ra and the roughness Rz. This not only fully reflects the height characteristics of the micro-geometry of the roughened surface, but also fully reflects the peak height of the profile of the roughened surface, making the roughness of the roughened surface more reasonable. This improves the adhesion performance of the roughened surface and ensures excellent adhesion between the metal foil and the application carrier such as the circuit board substrate, meeting the requirements of appropriate peel strength when pressed with the application carrier such as the circuit board substrate. At the same time, the water droplet angle Y of the roughened surface is also within a reasonable range, thus possessing excellent hydrophobicity, which can effectively prevent pollutants such as moisture in the air from being adsorbed onto the roughened surface.

[0058] As a preferred embodiment, based on any of the above embodiments, the roughened surface is provided with a plurality of roughening particles, each of which has a maximum vertical height of 0.1 to 2 μm and a maximum width of 0.2 to 2.5 μm.

[0059] The maximum vertical height refers to the vertical distance between the highest point of the coarsened particle and its root, and the maximum width refers to the maximum value of the width or diameter of the coarsened particle.

[0060] By employing the technical means of this invention, one side surface of the metal foil is roughened, and the maximum vertical height and maximum width range of each roughening particle are optimized, so that the roughness parameters of the roughened surface of the metal foil meet the requirements, thus ensuring the quality of the metal foil.

[0061] As a preferred embodiment, based on any of the above embodiments, the water droplet angle X on the other side opposite to the roughened surface is less than 60°.

[0062] During application, the metal foil can be pressed with an application carrier through its roughened surface. The other side, opposite to the roughened surface, is usually bonded to other peelable material layers, such as a carrier layer or a release layer, during production. In applications, such as in the circuit board field, after the peelable material layers are peeled off, subsequent processes such as circuit etching are performed on the other side opposite to the roughened surface. In the new energy battery field, the other side opposite to the roughened surface needs to be bonded with battery electrolysis reaction material.

[0063] In this embodiment of the invention, the water droplet angle X on the other side of the roughened surface 1 is further optimized. Specifically, the water droplet angle on the other side opposite to the roughened surface 1 satisfies X < 60°, for example, it can be 58°, 55°, 50°, 45°, 40°, 38°, 35°, 30°, 25°, 20°, 15°, 10° or 5°, etc. Of course, the specific value of the water droplet angle X can be set according to the actual usage requirements, which will not be elaborated further here.

[0064] By employing the technical means of this invention, the opposite side of the roughened surface 1 of the metal foil has better hydrophilicity. This results in stronger adhesion to the hydrophilic dry film during circuit board manufacturing, better protection of the circuit during etching, prevention of defective etching, and assurance of high etching yield. Simultaneously, the hydrophilicity of the metal foil surface facilitates the spread of the etching solution, accelerating the etching rate and improving production efficiency. Furthermore, in applications with new energy batteries, excellent surface hydrophilicity ensures good adhesion between the metal foil and the electrolytic material, preventing the electrolytic material from detaching from the metal foil surface or causing bubbling during battery operation, thus guaranteeing battery performance.

[0065] The oxidation rate, peel strength under the same hot-pressing conditions, and scrap rate of etched lines of ordinary metal foil and metal foil with the structure of the present invention were tested using specific examples.

[0066] In this embodiment of the invention, the specific methods for testing the arithmetic mean roughness Ra and the teardrop angle Y of the roughened surface are as follows:

[0067] The metal foil sample was cut into 100mm×150mm pieces. The arithmetic mean roughness Ra of the roughened surface of the metal foil sample was tested and recorded as the arithmetic mean roughness Ra value of the roughened surface. The water droplet angle value of the roughened surface of the metal foil sample was tested using a water droplet angle tester and recorded as the water droplet angle Y of the roughened surface.

[0068] Let A represent the metal foil product of this invention. Four metal foil samples (A1, A2, A3, and A4) were randomly selected and compared with commercially available ordinary metal foil product B.

[0069] Metal foil A1: The water droplet angle of the roughened surface is Y = 134.475°, and the arithmetic mean roughness is Ra = 0.183;

[0070] Metal foil A2: The water droplet angle of the roughened surface is Y = 135.503°, and the arithmetic mean roughness is Ra = 0.226.

[0071] Metal foil A3: The water droplet angle of the roughened surface is Y = 138°, and the arithmetic mean roughness is Ra = 0.205;

[0072] Metal foil A4: The water droplet angle of the roughened surface is Y = 120°, and the arithmetic mean roughness is Ra = 0.155;

[0073] Metal foil B: The water droplet angle of the roughened surface is Y = 103.015°, and the arithmetic mean roughness is Ra = 0.206;

[0074] The test data and comparison results are shown in Table 1:

[0075] Table 1

[0076]

[0077] The oxidation rate of the metal foil refers to the percentage of 100 randomly selected samples that have undergone oxidation after being stored under the same conditions for a certain period of time.

[0078] Therefore, compared with ordinary metal foils sold on the market, the metal foil with the structure of the present invention has a lower oxidation rate on the roughened surface, higher peel strength, and a lower scrap rate of the etched lines. All its performance is superior to ordinary commercially available products.

[0079] This invention provides a metal foil in which the arithmetic mean roughness Ra of the roughened surface satisfies the following functional relationship with the water droplet angle Y: Y = -6672.5 × Ra 2With a value of +2761.3×Ra-147.36, Ra>0, and Y>90°, the roughened surface of the metal foil exhibits good hydrophobicity. When applied to applications requiring hydrophobicity, such as printed circuit boards, this effectively prevents the adsorption of moisture and other contaminants from the air onto the roughened surface. This effectively solves various problems caused by oxidation of the roughened surface due to the adsorption of moisture and other contaminants, which can lead to decreased circuit conductivity or even insulation. It also reduces oxidation and contamination of the metal foil surface, simplifies environmental requirements for transportation and storage, and reduces the need for cleaning before application. Furthermore, optimizing the hydrophobicity of the roughened surface prevents poor bonding and loose adhesion between the roughened surface and the resin adhesive during the subsequent lamination process between the metal foil and the circuit board substrate. This ensures excellent bonding between the metal foil and the circuit board substrate, as well as sufficient adhesion to the adhesive, reducing the possibility of blistering and board bursting, increasing product yield, and saving production costs. Furthermore, the embodiments of the present invention further optimize the range of the water droplet angle Y of the roughened surface to 120° to 139°, and / or the most reasonable range of the arithmetic mean roughness Ra of the roughened surface to 0.16 to 0.3 μm, so that the water droplet angle and roughness of the roughened surface are both within a reasonable range, thereby enabling the roughened surface to have excellent hydrophobicity, adhesion and peel strength.

[0080] For a preferred embodiment, see Figure 3 This is a schematic diagram of the structure of a second type of metal foil provided in an embodiment of the present invention. The metal foil includes a conductive layer 2, one side of which is the roughened surface 1.

[0081] In this embodiment of the invention, the main structure of the metal foil includes a conductive layer 2. In practical applications, such as in the field of circuit boards, the conductive layer 2 is thermally bonded to the substrate of the circuit board. Similarly, in the field of batteries, the metal foil serves as the negative electrode material, and the conductive layer 2 is thermally bonded to the negative electrode active material. The side of the conductive layer 2 used for bonding with the substrate of the circuit board or the negative electrode active material is designated as the roughened surface 1, thereby increasing the adhesion of the conductive layer 2 and reducing bubbling, wrinkling, and cracking during bonding.

[0082] The conductive layer 2 is composed of a metal with good conductivity and low resistivity. The conductive layer 2 includes a single-metal conductive layer and / or an alloy conductive layer; wherein the single-metal conductive layer is made of any one of copper, aluminum, zinc, nickel, silver, gold, titanium, chromium and cobalt, and the alloy conductive layer is made of any two or more of copper, aluminum, zinc, nickel, silver, gold, titanium, chromium and cobalt, or it can be made of any two or more of copper, aluminum, zinc, nickel, silver, gold, titanium, chromium and cobalt and other materials.

[0083] Preferably, the conductive layer 2 is an ultra-thin metal layer with a thickness of 1–6 μm. More preferably, it is 1–5 μm, making the metal foil product thinner and lighter, and more practical.

[0084] In practice, a conductive layer 2 of a metal foil can be formed first, and then coarsened particles 11 can be formed on the conductive layer 2 through other processes. Alternatively, the conductive layer 2 of the metal foil and the coarsened particles 11 can be formed as a single integral structure through a one-step molding process. It should be noted that the material of the coarsened particles 11 can be the same as, partially the same as, or different from, the material of the conductive layer 2; this is not limited here.

[0085] For a preferred embodiment, see Figure 4 This is a schematic diagram of the structure of a third type of metal foil provided in an embodiment of the present invention. The metal foil includes a conductive layer 2 and a carrier layer 3, wherein the carrier layer 3 is disposed on the side of the conductive layer 2 that is not the roughened surface 1.

[0086] In this embodiment of the invention, the metal foil has a multilayer structure, including a conductive layer 2 and a carrier layer 3 stacked sequentially. One side of the conductive layer 2 is a roughened surface 1, and the carrier layer 3 is disposed on the other side.

[0087] The carrier layer 3 can be used to support and protect the conductive layer 2, so that the conductive layer 2 is not damaged by external contact or collision. After the metal foil is pressed with the circuit board at high temperature, the carrier layer 3 needs to be peeled off.

[0088] The carrier layer 3 is made of metallic or non-metallic materials. The metallic materials include at least one of the following metallic elements: copper, aluminum, zinc, nickel, chromium, iron, silver, and gold; the non-metallic materials include organic thin films, etc. Since the carrier layer 3 mainly serves a load-bearing function, it needs a certain thickness. When the carrier layer 3 is a material containing metallic elements such as copper, aluminum, or zinc, the thickness of the carrier layer is preferably 5-50 μm, more preferably 8-35 μm, for example, it can be 8 μm, 10 μm, 12 μm, 15 μm, 18 μm, 20 μm, 25 μm, 30 μm, 35 μm, etc. When the carrier layer is a non-metallic material such as an organic thin film, the thickness of the carrier layer is preferably 10-100 μm, for example, it can be 10 μm, 15 μm, 18 μm, 20 μm, 25 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, etc. Of course, the specific thickness of the carrier layer 3 can be set according to the actual usage requirements, which will not be elaborated further here.

[0089] The carrier layer 3 can be separated from the conductive layer 2 by a peelable or non-peelable method. When the carrier layer 3 is removed by a non-peelable method, such as laser etching, chemical etching, polishing, or plasma removal, the method can be such as manual peeling or removal using mechanical equipment.

[0090] Preferably, see Figure 5 This is a schematic diagram of the structure of a fourth type of metal foil provided in an embodiment of the present invention. The metal foil includes a conductive layer 2 and a carrier layer 3, and further includes a release layer 4, which is disposed between the carrier layer 3 and the conductive layer 2. That is, the metal foil includes a carrier layer 3, a release layer 4 and a conductive layer 2 stacked sequentially, and the side of the conductive layer 2 away from the release layer 4 is the roughened surface 1.

[0091] In this embodiment of the invention, when the carrier layer 3 is removed by peeling, the peeling method is: to remove it by peeling off the peeling layer 4, that is, to separate the carrier layer 3 from the conductive layer 2 by peeling off the peeling layer 4.

[0092] Meanwhile, the presence of the release layer can prevent metal migration between the conductive layer 2 and the carrier layer 3. Furthermore, the release layer 4 can cover or fill the uneven surface of the carrier layer 3, making the conductive layer 2 formed on the other surface of the release layer 4 smoother, more uniform and denser, reducing the occurrence of pinholes, which is beneficial for the fabrication of subsequent circuits.

[0093] Preferably, the release layer 4 is made of a metallic or non-metallic material. The metallic material includes any one or more of molybdenum, titanium, and niobium; the non-metallic material includes silicon, graphite, organic polymers, 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 agent release layer, a silicone oil release layer, or a nitrogen-based release layer. The release layer can be formed by coating and drying a release agent. In one embodiment, the release agent may include HDPE (high-density polyethylene) and PMA (propylene glycol methyl ether acetate) solvent, etc. When using the above two release agents, the mass ratio of HDPE to PMA is preferably (1-5):7. In another embodiment, the release agent may include a fluorinated release agent and a solvent; wherein the volume ratio of fluorinated release agent to solvent is preferably (5-30):1. It is understood that there are no special limitations on the types of solvents mentioned above; conventional release agent solvents in the art can be used, such as butanone, which does not constitute a limitation of the present invention.

[0094] Preferably, when the material of the release layer 4 is a metallic material, the thickness of the release layer is 2–100 nm; or, when the material of the release layer is 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 4 can be set according to actual usage requirements, and will not be elaborated further here.

[0095] The structure of the release layer in the embodiment of the invention can ensure appropriate adhesive strength while retaining a certain degree of adhesiveness, so that the metal foil will not delaminate during the hot pressing process.

[0096] In a preferred embodiment, the carrier layer 3 and / or the release layer 4 of the metal foil are filled with a heat-absorbing medium. By adding the heat-absorbing medium, when the metal foil is hot-pressed onto a circuit board substrate or hot-pressed together with a negative electrode active material in a new energy battery, the heat-absorbing medium can absorb heat, reducing the heat on the bonding surface of the conductive layer 2, and further reducing the occurrence of blistering, wrinkling, cracking, etc. during the bonding of the metal foil.

[0097] Preferably, the heat-absorbing medium is filler particles.

[0098] See Figures 6 to 8 This is a schematic diagram of the structure of the fifth to seventh types of metal foil provided in the embodiments of the present invention. In the metal foil, the filler particles are filled in three ways: one is to fill only the carrier layer 3 with the first filler particle 31, as detailed in [reference needed]. Figure 6 Secondly, the second filler particles 41 are filled only in the peeling layer 4, as detailed in [reference needed]. Figure 7 Third, the carrier layer 3 is filled with first filler particles 31, and the release layer 4 is filled with second filler particles 41. For details, please refer to [link to relevant documentation]. Figure 8.

[0099] Understandably, Figures 6 to 8 The shape of the filler particles described herein is merely exemplary. Due to differences in processing methods and parameters, the filler particles may also be in other shapes such as clusters, ice-like structures, stalactite-like structures, or dendritic structures. Furthermore, the heat-absorbing medium in the embodiments of the present invention is not limited to filler particles, nor is it limited to the shapes shown in the figures and described above. Any medium that fills the carrier layer or the release layer and has a heat-absorbing effect is within the protection scope of the present invention.

[0100] For a preferred embodiment, see Figure 9 This is a schematic diagram of the structure of the eighth type of metal foil provided in this embodiment of the invention. The metal foil includes a conductive layer 2, a carrier layer 3, and a release layer 4, and also includes an adhesive layer 5, which is disposed between the carrier layer 3 and the release layer 4. That is, the metal foil includes a carrier layer 3, an adhesive layer 5, a release layer 4, and a conductive layer 2 stacked sequentially, and the side of the conductive layer 2 away from the release layer 4 is the roughened surface 1.

[0101] In this embodiment of the invention, an adhesive layer 5 is added between the carrier layer 3 and the release layer 4 to improve the adhesion between them. During peeling, the two layers will not separate, and the increased peeling force effectively improves the peeling effect. Simultaneously, the presence of the adhesive layer 5 and the release layer 4 covers the uneven surface of the carrier layer 3, making the conductive layer 2 formed on the other side of the release layer 4 smoother, more uniform, and denser, reducing pinholes and facilitating subsequent circuit fabrication.

[0102] Preferably, the adhesive layer can be a metallic adhesive layer or a non-metallic adhesive layer. When it is a metallic adhesive layer, the metallic adhesive layer is made of any one or more materials selected from copper, zinc, nickel, iron, and manganese; or, the metallic adhesive layer is made of one of copper or zinc and one of nickel, iron, and manganese. When it is a non-metallic adhesive layer, its material 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 resins, epoxy resins, thermoplastic polyimides, urethane-based, melamine-based or alkyd thermosetting resins, BT resins, and ABF resins.

[0103] For a preferred embodiment, see Figure 10This is a schematic diagram of the structure of a ninth type of metal foil provided in an embodiment of the present invention. The metal foil includes a conductive layer 2, a carrier layer 3, and a release layer 4, and also includes a first anti-oxidation layer 6, which is disposed on the side of the conductive layer 2 closest to the release layer 4. That is, the metal foil includes a carrier layer 3, a release layer 4, a first anti-oxidation layer 6, and a conductive layer 2 stacked sequentially, and the side of the conductive layer 2 away from the release layer 4 is the roughened surface 1.

[0104] In this embodiment of the invention, a first anti-oxidation layer 6 is provided between the release layer 4 and the conductive layer 2. This improves the anti-oxidation performance of the conductive layer 2, prevents it from oxidizing and forming an oxide film that would affect its conductivity and thermal conductivity, and reduces the number of pinholes on the metal foil surface, ensuring the integrity of the etched circuitry after subsequent bonding to the circuit board substrate. Furthermore, since the adhesion between the first anti-oxidation layer 6 and the release layer 4 is relatively weak, it also improves the release effect.

[0105] Optionally, the first anti-oxidation layer is made of at least one of metals such as nickel, copper, chromium, and zinc, and / or an alloy including at least one of them. Exemplarily, the first anti-oxidation layer 6 is formed on the surface of the conductive layer 2 by processes including chemical plating, chemical micro-electroplating, etc.

[0106] For a preferred embodiment, see Figure 11 This is a schematic diagram of the tenth type of metal foil provided in this embodiment of the invention. The metal foil includes a conductive layer 2, a carrier layer 3, a release layer 4, and a first anti-oxidation layer 6, and also includes a second anti-oxidation layer 7, which is disposed on the side of the conductive layer 2 away from the release layer 4. That is, the metal foil includes a carrier layer 3, a release layer 4, a first anti-oxidation layer 6, a conductive layer 2, and a second anti-oxidation layer 7 stacked sequentially, and the side of the conductive layer 2 away from the release layer 4 is the roughened surface 1.

[0107] In this embodiment of the invention, a second anti-oxidation layer 7 is added to the roughened surface 1 of the conductive layer 2, which can effectively protect the oxidation resistance of the bonding surface between the conductive layer 2 and the circuit board substrate, and by selecting a suitable material, the bonding performance between the conductive layer 2 and the substrate can be improved synergistically.

[0108] Optionally, the second anti-oxidation layer is made of at least one of metals such as nickel, copper, chromium, and zinc, and / or an alloy of at least one of them. Exemplarily, the second anti-oxidation layer 7 is formed on the roughened surface 1 of the conductive layer 2 by processes including chemical plating, chemical micro-electroplating, etc.

[0109] For a preferred embodiment, see Figure 12This is a schematic diagram of the eleventh type of metal foil provided in this embodiment of the invention. The metal foil includes a conductive layer 2, a carrier layer 3, and a release layer 4, and also includes a resin layer 8, which is disposed on the side of the conductive layer 2 away from the release layer 4. That is, the metal foil includes a carrier layer 3, a release layer 4, a conductive layer 2, and a resin layer 8 stacked sequentially, and the side of the conductive layer 2 away from the release layer 4 is the roughened surface 1.

[0110] In this embodiment of the invention, a resin layer 8 is added to the roughened surface 1 of the conductive layer 2, that is, a resin layer 8 is provided on the surface where the conductive layer 2 is bonded to the circuit board substrate, which can achieve functions such as anti-oxidation, moisture-proof, and waterproof, and can also improve the adhesion performance with the substrate.

[0111] The resin layer 8 is made of at least one of thermoplastic resin, thermosetting resin, BT resin, and ABF value, wherein the thermoplastic resin includes polystyrene-based, vinyl acetate-based, polyester-based, polyethylene-based, polyamide-based, rubber-based, or acrylate-based thermoplastic resins; the thermosetting resin includes phenolic, epoxy, thermoplastic polyimide, urethane-based, melamine-based, or alkyd thermosetting resins.

[0112] It should be noted that the structure of the metal foil provided in the embodiments of the present invention is not limited to the multi-layer structure of the above embodiments. In practical applications, other material layers and additional structures can be added as needed, which do not constitute a limitation of the present invention.

[0113] Using the technical means of this invention, the metal foil adopts a multi-layer structure. By optimizing the functional relationship between the water droplet angle Y and the arithmetic mean roughness Ra of the roughened surface of the metal foil, the water droplet angle and roughness of the roughened surface are both within an optimal range. This results in the roughened surface having excellent hydrophobicity, making it suitable for various applications requiring hydrophobicity. It effectively prevents pollutants such as moisture in the air from adsorbing onto the roughened surface, thus solving various adverse problems caused by oxidation of the roughened surface of the metal foil due to the adsorption of pollutants such as moisture in the air, which can lead to decreased circuit conductivity or even insulation. This reduces oxidation and contamination of the metal foil surface, simplifies the environmental requirements for the transportation and storage of the metal foil, and reduces the cleaning process before application.

[0114] Example 2

[0115] See Figure 13This is a schematic diagram of a circuit board structure provided in an embodiment of the present invention. The present invention provides a circuit board comprising a circuit board substrate 9 and a metal foil as described in any of the above embodiments; the metal foil includes a roughened surface 1, and the roughened surface 1 is pressed against the circuit board substrate.

[0116] It should be noted that the structure of the metal foil can refer to the structure of the metal foil described in any of the above embodiments, and will not be repeated here.

[0117] By employing the technical means of this invention, the water droplet angle Y and the arithmetic mean roughness Ra of the roughened surface of the metal foil are optimized through a functional relationship. The roughness and water droplet angle of the roughened surface are controlled within a reasonably optimal range, giving it excellent hydrophobic properties. This effectively prevents contaminants such as moisture in the air from adsorbing onto the roughened surface, making it suitable for the fabrication of high-frequency, high-density circuit boards. It avoids problems such as poor adhesion and loose bonding between the roughened surface and the resin adhesive during the lamination process between the metal foil and the substrate, ensuring excellent bonding between the metal foil and the circuit board substrate, as well as sufficient adhesion to the adhesive. This reduces the possibility of blistering and board bursting, increases product yield, and saves costs. Furthermore, the metal foil also meets the requirements for suitable peel strength during lamination with the substrate.

[0118] Example 3

[0119] The present invention also provides a copper clad laminate, specifically a flexible copper clad laminate (FCCL), also known as a flexible copper clad laminate, wherein the flexible copper clad laminate includes the metal foil as described in any of the above embodiments.

[0120] It should be noted that the structure of the metal foil can refer to the structure of the metal foil described in any of the above embodiments, and will not be repeated here.

[0121] The flexible copper-clad laminate structure includes: a metal foil layer, an adhesive layer, and another metal foil layer, or includes: a metal foil layer and an adhesive layer. The adhesive layer material can be polyimide (PI), thermoplastic polyimide (TPI), resin, etc.

[0122] Compared to existing technologies, using metal foil with an improved carrier layer as the material for the flexible copper-clad laminate has the following advantages: By optimizing the functional relationship between the water droplet angle Y and the arithmetic mean roughness Ra of the roughened surface of the metal foil, the roughness and water droplet angle of the roughened surface are controlled within a reasonable and optimal range, giving it excellent hydrophobic properties. This effectively prevents pollutants such as moisture in the air from adsorbing onto the roughened surface. At the same time, it ensures good adhesion strength and gives the carrier layer suitable peel strength, thereby improving the yield of the manufactured copper-clad laminate products. In subsequent use, the product performance is more stable and reliable, with less high-frequency signal transmission loss and reduced production costs.

[0123] In addition, the copper-clad laminate can also be resin-coated copper foil (RCC), which is mainly used for high-density circuits. In this case, the roughened surface of the metal foil is away from the side of the copper foil coated with resin.

[0124] Example 4

[0125] This invention also provides a semiconductor material, which includes the metal foil described in any of the above embodiments.

[0126] It should be noted that the structure of the metal foil can refer to the structure of the metal foil described in any of the above embodiments, and will not be repeated here.

[0127] By employing the technical means of this invention, and using the metal foil as a semiconductor material, the water droplet angle Y and the arithmetic mean roughness Ra of the roughened surface of the metal foil are optimized through a functional relationship. The roughness and water droplet angle of the roughened surface are controlled within a reasonable and preferred range, giving it excellent hydrophobic properties. This effectively prevents pollutants such as moisture in the air from adsorbing onto the roughened surface, thereby improving the quality of the metal foil product. It is suitable for manufacturing semiconductor devices and integrated circuits, improving the quality and processing efficiency of semiconductor devices and integrated circuits, and reducing the defect rate of semiconductor devices and integrated circuits.

[0128] Example 5

[0129] This invention also provides a negative electrode material for use in batteries, the negative electrode material comprising the metal foil described in any of the above embodiments.

[0130] It should be noted that the structure of the metal foil can refer to the structure of the metal foil described in any of the above embodiments, and will not be repeated here.

[0131] This invention also provides a battery, wherein the negative electrode material of the battery includes a metal foil as described in any of the above embodiments.

[0132] Compared to existing technologies, using the aforementioned metal foil as the negative electrode carrier or current collector in the above-mentioned batteries has the following advantages: By optimizing the functional relationship between the water droplet angle Y and the arithmetic mean roughness Ra of the roughened surface of the metal foil, the roughness and water droplet angle of the roughened surface are controlled within a reasonably optimal range, giving it excellent hydrophobic properties. This effectively prevents pollutants such as moisture in the air from adsorbing onto the roughened surface, improving the quality of the metal foil product. The metal foil can be used in new energy batteries, such as lithium-ion batteries and sodium-ion batteries, as a negative electrode current collector and carrier material. Due to its rough surface, the battery's negative electrode active material is tightly bonded to the metal foil, making it less prone to detachment during battery use. Under strong impacts or during battery charging and discharging, the metal foil material is less likely to break or deform, which is beneficial for improving the service life and safety of new energy batteries.

[0133] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A metal foil, characterized in that, The roughened surface includes a surface whose arithmetic mean roughness Ra and the water droplet angle Y satisfy the following functional relationship: Y = -6672.5 × Ra 2 +2761.3×Ra-147.36, and the correlation coefficient R of the aforementioned functional relationship. 2 It is 0.9973; The water droplet angle Y of the roughened surface is 120° to 139°, and the arithmetic mean roughness Ra of the roughened surface is 0.16 to 0.3 μm.

2. The metal foil as described in claim 1, characterized in that, The roughness Rz of the roughened surface is less than or equal to 2 μm.

3. The metal foil as described in claim 1, characterized in that, The water droplet angle X on the side opposite to the roughened surface is less than 60°.

4. The metal foil as described in claim 1, characterized in that, The metal foil includes a conductive layer, a release layer, and a carrier layer stacked sequentially, with one side of the conductive layer being the roughened surface; the release layer and the carrier layer are disposed on the other side of the conductive layer opposite to the roughened surface.

5. The metal foil as described in claim 4, characterized in that, The conductive layer is made of at least one of the following metallic elements: copper, aluminum, zinc, nickel, gold, silver, chromium, and cobalt, and / or an alloy thereof.

6. The metal foil as described in claim 5, characterized in that, The thickness of the conductive layer is 1–6 μm.

7. The metal foil as described in claim 5, characterized in that, The material of the carrier layer includes at least one of the following metallic elements: copper, aluminum, zinc, nickel, chromium, iron, silver, and gold, in which case the thickness of the carrier layer is 5 to 50 μm; or, the material of the carrier layer is an organic thin film, in which case the thickness of the carrier layer is 10 to 100 μm.

8. The metal foil as described in claim 5, characterized in that, The material of the release layer is a metallic material, and the thickness of the release layer is 2 to 100 nm; or, the material of the release layer is a non-metallic material, and the thickness of the release layer is less than or equal to 1 μm.

9. A circuit board, characterized in that, It includes a circuit board substrate and a metal foil as described in any one of claims 1 to 8; the roughened surface of the metal foil is pressed against the circuit board substrate.

10. A copper-clad laminate, characterized in that, The copper-clad laminate comprises the metal foil as described in any one of claims 1 to 8.

11. A semiconductor material, characterized in that, The semiconductor material includes the metal foil as described in any one of claims 1 to 8.

12. A negative electrode material for use in batteries, characterized in that, The negative electrode material includes the metal foil as described in any one of claims 1 to 8.

13. A battery, characterized in that, The negative electrode material of the battery includes the metal foil as described in any one of claims 1 to 8.

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