Carrier of metal foil, metal foil and its application

Abstract

The present invention discloses a carrier for a metal foil, the metal foil and their applications. The carrier includes opposite first and second surfaces, the roughness Rz of the first surface is greater than the roughness Rz of the second surface, and the roughness Rz of the first surface and the water contact angle Y of the first surface satisfy the following functional relationship: Y = -24.152×Rz<supgt;2< / supgt> + 270.39×Rz - 649.43, Rz > 0, Y ≥ 90°, and the correlation coefficient R<supgt;2< / supgt> of the functional relationship is 0.9915. By adopting the technical means of the present invention, by optimizing the relationship between the roughness and the water contact angle of the outer surface of the carrier of the metal foil, the hydrophobicity of the outer surface of the carrier is effectively improved, and problems such as the surface of the carrier being wet and air oxidation caused by the adsorption of pollutants such as moisture in the air on the outer surface of the carrier can be well overcome, and the carrier can more effectively play the role of carrying and protecting the metal foil.

Description

Technical Field

[0001] The present invention relates to the technical field of metal foils, and in particular to a metal foil carrier, the metal foil and applications thereof. Background Art

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

[0003] In the prior art, the surface of the metal foil is often covered with a carrier to support and protect the metal layer in the metal foil. This requires that the metal foil carrier not only has good strength to support the extremely thin metal foil, but also requires that the physical and chemical properties of its two surfaces must meet certain requirements to facilitate the transportation and protection of the extremely thin metal foil. Since the different sides of the metal foil carrier have different functions in the processing technology and actual application scenarios, the specific requirements for the physical properties of the different sides of the carrier are also different. For the side of the carrier that is not in contact with the metal layer of the metal foil, since this side is exposed to the air environment, if the hydrophilicity of the surface is strong, it is easy to cause itself to absorb water vapor in the air, etc., causing the surface to be easily oxidized and the storage time is greatly shortened. At the same time, the severely oxidized carrier will also greatly increase the oxidation probability of the ultra-thin metal foil it carries. In the subsequent client application, the carrier caused by oxidation is easy to increase in brittleness during the peeling process, and then the oxidized powder falls off from its surface, causing the increase of pollutants such as space dust during the peeling process. The situation of the peeled ultra-thin metal foil surface adsorbing the above pollutants also increases accordingly. When the customer uses the ultra-thin metal foil, it is necessary to set up additional cleaning and other processes to remove the pollutants caused by the dust peeling off the surface of the carrier, resulting in an increase in the complexity of the customer's process and an increase in the application cost. Therefore, the surface of the carrier needs to have a certain hydrophobicity. However, the current metal foil carrier is still difficult to meet such requirements. Therefore, providing a metal foil carrier that can meet the above performance requirements is an urgent problem to be solved by technicians in this field. Summary of the invention

[0004] The purpose of the embodiments of the present invention is to provide a metal foil carrier, a metal foil and applications thereof. By optimizing the relationship between the roughness of the outer surface of the metal foil carrier and the water drop angle, the hydrophobicity of the outer surface of the carrier is effectively improved, which can more effectively carry and protect the metal foil and reduce the contamination of the metal foil application surface during the peeling process.

[0005] To achieve the above object, an embodiment of the present invention provides a carrier for a metal foil. The carrier includes opposite first and second surfaces. The roughness Rz of the first surface is greater than the roughness Rz of the second surface, and the roughness Rz of the first surface and the water contact angle Y of the first surface satisfy the following functional relationship:

[0006] Y = -24.152×Rz 2 +270.39×Rz - 649.43, Rz > 0, Y ≥ 90°, and the correlation coefficient R

[0007] of the functional relationship is 2 0.9915.

[0008] As an improvement to the above solution, the water contact angle Y of the first surface is 95° - 106°.

[0009] As an improvement to the above solution, the roughness Rz of the first surface is 2.8 - 5 μm.

[0010] As an improvement to the above solution, the root mean square roughness Rq of the first surface is 0.6 - 1.3 μm.

[0011] As an improvement to the above solution, the roughness Rz of the second surface is 0.9 - 1.5 μm.

[0012] As an improvement to the above solution, the water contact angle Y of the first surface is 1.6 - 5 times the water contact angle X of the second surface.

[0013] As an improvement to the above solution, the thickness of the carrier is 6 - 35 μm.

[0014] An embodiment of the present invention further provides a metal foil, including a metal layer and the carrier for the metal foil according to any one of the above. The first surface of the carrier is the side surface away from the metal layer, and the second surface of the carrier is the side surface close to the metal layer.

[0015] As an improvement to the above solution, the material of the carrier includes at least one of the following metal elements: copper, aluminum, zinc, nickel, chromium, iron, silver, and gold; or, the material of the carrier is an organic film.

[0016] As an improvement to the above solution, the side of the metal layer away from the carrier is a roughened surface, and the roughened surface has a number of roughened particles; and the roughness Rz of the roughened surface is less than or equal to 2 μm.

[0017] As an improvement to the above solution, the material of the metal layer includes at least one of the metal elements copper, aluminum, zinc, nickel, silver, gold, chromium, and cobalt and / or an alloy of at least one of them; and the thickness of the metal layer is 1 - 5 μm.

[0018] As an improvement of the above solution, the metal foil further includes a release layer, the release layer is disposed between the carrier and the metal layer, and the thickness of the release layer is 1 to 8 nm.

[0019] An embodiment of the present invention further provides a circuit board, including a circuit board substrate and the metal foil as described in any one of the above; one side of the metal layer away from the carrier is press-fitted with the circuit board substrate.

[0020] An embodiment of the present invention further provides a copper-clad laminate, and the copper-clad laminate includes the metal foil as described in any one of the above.

[0021] An embodiment of the present invention further provides a semiconductor material, and the semiconductor material includes the metal foil as described in any one of the above.

[0022] An embodiment of the present invention further provides a negative electrode material for a battery, and the negative electrode material includes the metal foil as described in any one of the above.

[0023] An embodiment of the present invention further provides a battery, and the negative electrode material of the battery includes the metal foil as described in any one of the above.

[0024] Compared with the prior art, the carrier, the metal foil and its application of the metal foil disclosed in the embodiment of the present invention, the carrier of the metal foil includes opposite first and second surfaces, the roughness Rz of the first surface is greater than the roughness Rz of the second surface, and the roughness Rz of the first surface and the water contact angle Y of the first surface satisfy the following functional relationship: Y = -24.152 × Rz 2+270.39×Rz - 649.43, where Rz > 0 and Y ≥ 90°. By adopting the technical means of the embodiments of the present invention, the outer surface of the carrier of the metal foil has good hydrophobicity. Therefore, during the application process, the outer surface of the carrier is not easily contaminated by objects such as moisture and dust in the air, and can maintain a relatively dry and clean surface state, and is not easily oxidized. When the carrier is used as the carrier of the metal foil, if the surface of the carrier is easily oxidized, it is difficult to provide good protection for the key material layer in the metal foil. For example, when the metal foil is in the high-temperature lamination process, due to the high hardness of the oxidation points on the carrier, pits and protrusions are formed on the surface of the extremely thin metal layer during the lamination process, resulting in the problem of uneven surface of the extremely thin metal layer. In subsequent applications, it may cause relatively large line transmission losses, and may also cause poor adhesion when the metal layer is laminated with application carriers such as circuit boards, resulting in problems such as skewing, blistering, and wrinkling of the metal layer. In addition, it is also possible that the oxidation points fall off during the lamination process and adhere to the surface of the press platen, contaminating the press and thus affecting the subsequent lamination process. However, the carrier of the embodiments of the present invention can better play the role of carrying and protecting the metal foil because it can maintain a dry, clean, and intact state, and can also simplify the environmental requirements for the transportation, storage, etc. of the metal foil, reducing the cleaning process before the application of the metal foil. At the same time, when the carrier is recycled, the surface in contact with the outside air has good hydrophobicity, which can further simplify the subsequent reuse process and improve the recovery rate of the carrier. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a schematic structural diagram of a carrier of a metal foil provided by an embodiment of the present invention;

[0026] Figure 2 is a top-view electron microscope image of the first surface of the carrier of the metal foil in an embodiment of the present invention;

[0027] Figure 3 is a schematic structural diagram of a first metal foil provided by an embodiment of the present invention;

[0028] Figure 4 is a schematic structural diagram of a second metal foil provided by an embodiment of the present invention;

[0029] Figure 5 is a schematic structural diagram of a third metal foil provided by an embodiment of the present invention;

[0030] Figure 6 is a schematic structural diagram of a fourth metal foil provided by an embodiment of the present invention;

[0031] Figure 7 is a schematic structural diagram of a fifth metal foil provided by an embodiment of the present invention;

[0032] Figure 8 It is a schematic structural diagram of the sixth metal foil provided by an embodiment of the present invention;

[0033] Figure 9 It is a schematic structural diagram of the seventh metal foil provided by an embodiment of the present invention;

[0034] Figure 10 It is a schematic structural diagram of the eighth metal foil provided by an embodiment of the present invention;

[0035] Figure 11 It is a schematic structural diagram of the ninth metal foil provided by an embodiment of the present invention;

[0036] Figure 12 It is a schematic structural diagram of the tenth metal foil provided by an embodiment of the present invention;

[0037] Wherein, 1 is a carrier; 11 is a first surface; 12 is a second surface; 13 is a first filler particle; 2 is a metal layer; 21 is a roughened surface; 22 is a roughened particle; 3 is a release layer; 31 is a second filler particle; 4 is an adhesive layer; 5 is a first anti-oxidation layer; 6 is a second anti-oxidation layer; 7 is a resin layer. Specific embodiments

[0038] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

[0039] In the description of the specification and the claims, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", "front", "rear", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the embodiments of the present invention, rather than indicating or implying that the device or component referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the embodiments of the present invention.

[0040] In addition, the terms first, second, etc. in the specification and the claims are only used for the purpose of distinguishing the description of the same technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features, nor necessarily describing the order or time sequence. The terms can be interchanged under appropriate circumstances. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of the features.

[0041] Example 1

[0042] See Figure 1 and Figure 2 , Figure 1 FIG. 1 is a schematic structural diagram of a carrier for a metal foil provided by an embodiment of the present invention, Figure 2 and FIG. 2 is a top-down electron microscope image of the first surface of the carrier of the metal foil in the embodiment of the present invention. An embodiment of the present invention provides a carrier 1 for a metal foil. The carrier 1 includes opposite first surface 11 and second surface 12.

[0043] In practical applications, the carrier 1 can be applied to the application scenario of the metal foil, and is stacked with other material layers in the metal foil to carry and protect the material layer, so that the material layer is not damaged by external contact or collision, etc. After the metal foil and the circuit board are hot-pressed, the carrier 1 needs to be peeled off.

[0044] In the embodiment of the present invention, the first surface 11 of the carrier 1 is the surface on the side away from the metal foil, and the second surface 12 is the surface on the side close to the metal foil. That is, the carrier 1 is stacked with other material layers of the metal foil, such as a metal layer, through the second surface 12. The first surface 11 and the second surface 12 of the carrier 1 have a certain roughness. And, since the roughness of the two sides of the carrier 1 is different, the material layers contacted or carried during its production and application are also different. The roughness Rz of the first surface 11 of the carrier 1 is greater than the roughness Rz of the second surface 12.

[0045] And, the roughness Rz of the first surface and the water contact angle Y of the first surface satisfy the following functional relationship:

[0046] Y = -24.152×Rz 2 +270.39×Rz - 649.43, Rz > 0, Y ≥ 90°, and the correlation coefficient R of the functional relationship

[0047] is 0.9915. 2 is 0.9915.

[0048] It should be noted that the roughness Rz refers to the sum of the average value of the n largest profile peak heights and the average value of the n largest profile valley depths within the sampling length, where n ≥ 1; optionally, n = 5. The roughness Rz can fully reflect the peak height of the profile.

[0049] In practical applications, the hydrophobic property required for the first surface 11 of the carrier 1 is related to the size of the water contact angle Y and the roughness of this surface. Generally, the larger the water contact angle Y, the stronger the hydrophobicity; the smaller the water contact angle Y, the weaker the hydrophobicity; the larger the roughness, the stronger the hydrophobicity; the smaller the roughness, the weaker the hydrophobicity. In the embodiments of the present invention, by fitting the functional relationship between the roughness Rz and the water contact angle Y, there is a certain functional correlation between the roughness Rz of the first surface 11 of the carrier 1 and the water contact angle Y of this surface. When the water contact angle Y and the roughness Rz of the first surface 11 of the carrier 1 simultaneously satisfy the functional relationship of Y = -24.152×Rz 2 +270.39×Rz - 649.43, it can enable the first surface 11 to have a reasonable roughness range and a reasonable range value of the water contact angle at the same time, so that the hydrophobic property presented by the first surface 11 is better, meeting the hydrophobicity requirements for the outer surface of the carrier. And, the correlation coefficient R 2 of this functional relationship is 0.9915, and the correlation coefficient is close to 1, indicating that the fitting regression effect is good and the linear relationship between the roughness Rz and the water contact angle Y is strong.

[0050] By adopting the technical means of the embodiments of the present invention, the outer surface of the carrier of the metal foil has good hydrophobicity. Therefore, during the application process, the outer surface of the carrier is not easily contaminated by objects such as moisture and dust in the air, and can maintain a relatively dry and clean surface state, and is not easily oxidized at the same time. When the carrier is used as the carrier of the metal foil, if the surface of the carrier is easily oxidized, it is difficult to provide good protection for the key material layer in the metal foil. For example, when the metal foil is in the high-temperature lamination process, due to the high hardness of the oxidation points on the carrier, pits and protrusions are formed on the surface of the extremely thin metal layer during the lamination process, resulting in the problem of unevenness on the surface of the extremely thin metal layer. In subsequent applications, it may lead to relatively large line transmission losses, and may also cause poor adhesion when the metal layer is laminated with application carriers such as circuit boards, resulting in problems such as skewing, blistering and wrinkling of the metal layer. In addition, it is also possible that the oxidation points fall off during the lamination process and adhere to the surface of the press plate of the press, causing pollution to the press, and further affecting the subsequent lamination process. However, the carrier of the embodiments of the present invention can better play the role of carrying and protecting the metal foil because it can maintain a dry, clean and intact state, and can also simplify the environmental requirements for the transportation, storage, etc. of the metal foil, reduce the possibility of the metal foil being contaminated before application, and save the cleaning process. At the same time, when the carrier is recycled, the surface in contact with the outside air has good hydrophobicity, which can further simplify the subsequent reuse treatment process and improve the recovery rate of the carrier.

[0051] As an alternative embodiment, a preset roughening treatment is performed on the first surface 11, while no specific roughening treatment is performed on the second surface 12, such that the roughness Rz of the first surface 11 is greater than the roughness Rz of the second surface 12. Moreover, the specific value of the roughness Rz of the first surface 11 is controlled by the preset roughening treatment process.

[0052] It should be noted that the roughening treatment process for the surface of the carrier 1 includes: it can be achieved by setting the surface of the carrier 1 as an undulating non-planar surface, or by setting a number of minute unevennesses on the surface of the carrier 1, or by setting a number of raised roughening particles on the surface of the carrier 1. Of course, it can also be a combination of at least two of the above three implementation methods, which does not affect the beneficial effects achieved by the present invention.

[0053] Moreover, the minute unevennesses or the raised roughening particles provided on the surface of the carrier 1 can be in the shape of clusters, icicles, stalactites, dendrites or other shapes. Of course, the shapes of the minute unevennesses or the raised roughening particles are not limited to the above shapes, as long as they have the function of providing the surface roughness of the carrier, they are within the protection scope of the present invention. Moreover, in specific implementation, the carrier 1 can be first formed, and then minute unevennesses or raised roughening particles can be provided on the carrier 1 through other processes; of course, the carrier 1 can also be an integral structure formed by a one-step forming process. Moreover, the material of the minute unevennesses or the raised roughening particles can be the same as or different from the material of the carrier of the metal foil, which is not limited herein.

[0054] By adopting the technical means of the embodiment of the present invention, the first surface 11 of the carrier has a relatively large roughness, such that during the transmission of the metal foil, due to the existence of the rough surface of the carrier, the metal foil has better adhesion, and can avoid the problem that the metal foil is very likely to slip and skew during the conveying process due to the very flat and smooth surface of the transmission roller, thereby causing wrinkles in the winding and further resulting in the scrapping of the entire roll of copper foil. It can also avoid the influence on the product stability under the condition of high-temperature baking during the subsequent application process, and reduce the occurrence of problems such as blistering and cracking. The second surface 12 of the carrier is relatively smooth, such that the metal foil replicates the rough morphology of the second surface of the carrier and generates a relatively appropriate roughness, which is not too large, thereby avoiding the problem of excessive transmission loss during the application of the metal foil.

[0055] As a preferred embodiment, the water contact angle Y of the first surface is 95° to 106°.

[0056] In an embodiment of the present invention, on the first surface 11 of the carrier, the water contact angle Y and the roughness Rz satisfy the functional relationship of Y = -24.152×Rz 2 +270.39×Rz - 649.43, and the numerical range of the water contact angle Y of the first surface 11 is further optimized. The water contact angle Y of the first surface 11 is between 95° and 106°. For example, it can be 95°, 96°, 97°, 98°, 99°, 100°, 101°, 102°, 103°, 104°, 105° or 106°. Of course, the specific value of the water contact angle Y of the first surface 11 can be set according to actual use requirements, and no more details will be elaborated here.

[0057] By adopting the technical means of the embodiment of the present invention, the outer surface of the carrier has excellent hydrophobicity, is not easily contaminated by objects such as moisture and dust in the air, can maintain a relatively dry and clean surface state, is not easily oxidized at the same time, can play a better role in protecting and carrying the metal foil, and avoids problems such as oxidation, wrinkling, and blistering on the surface of the metal foil, further improving the quality of the metal foil. At the same time, when the water contact angle Y of the first surface is within the above numerical range, it can also make the first surface have a reasonable roughness Rz, improve the good adhesion strength between the metal foil and the surface of the transfer roller during the transfer process, and effectively meet the requirements of the appropriate peeling strength between the metal foil and the carrier during the application process, comprehensively improving the quality of the metal foil product.

[0058] As a preferred embodiment, the roughness Rz of the first surface is 2.8 - 5μm, and more preferably 3.0 - 4.5μm.

[0059] In an embodiment of the present invention, the numerical range of the roughness Rz of the first surface 11 is further optimized. The roughness Rz of the first surface 11 is between 2.8 - 5μm. For example, it can be 2.8μm, 3.0μm, 3.2μm, 3.5μm, 3.8μm, 4.0μm, 4.2μm, 4.5μm, 4.7μm, 5μm. Of course, the specific value of the roughness Rz of the first surface can be set according to actual use requirements, and no more details will be elaborated here.

[0060] By adopting the technical means of the embodiments of the present invention, a reasonable roughness is provided on the first surface, improving the good adhesion strength between the metal foil and the surface of the transfer roller during the transfer process, and effectively meeting the requirement of the appropriate peel strength between the metal foil and the carrier during the application process. Moreover, by optimizing the roughness Rz of the first surface 11, the water contact angle Y of the first surface of the carrier is also within a reasonable range, so that the outer surface of the carrier has appropriate hydrophobicity, which can effectively prevent pollutants such as moisture in the air from adsorbing on the outer surface of the carrier, resulting in the surface of the carrier being wet and oxidized by air, and then reducing or losing the protection and loading functions for the metal foil, leading to problems such as oxidation, wrinkling, and blistering on the surface of the metal foil, seriously affecting the quality of the metal foil.

[0061] As a preferred embodiment, the root mean square roughness Rq of the first surface is 0.6 - 1.3 μm.

[0062] It should be noted that the root mean square roughness Rq is specifically the root mean square value of the profile ordinate value Z(x) within a sampling length. The ordinate value Z(x) refers to the distance from each point on the profile to the profile center line, which can fully reflect the characteristics of the surface microgeometry in terms of height.

[0063] In the embodiments of the present invention, the numerical range of the root mean square roughness Rq of the first surface 11 of the carrier is further optimized. The root mean square roughness Rq of the first surface 11 is between 0.6 - 1.3 μm, for example, it can be 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, 1 μm, 1.2 μm, or 1.3 μm. Of course, the specific value of the root mean square roughness Rq of the first surface can be set according to actual usage requirements and will not be elaborated further here.

[0064] In the embodiment of the present invention, on the basis that the water contact angle Y and the roughness Rz of the first surface of the carrier satisfy the above functional relationship, the numerical range of the root mean square roughness Rq of the first surface is further optimized. By combining the arithmetic mean roughness Ra and the roughness Rz, the rough characteristics of the roughened surface are characterized, which not only fully reflects the characteristics of the microscopic geometry of the roughened surface in terms of height, but also fully reflects the peak height of the profile of the roughened surface, making the roughness of the first surface more reasonable, improving the good contact between the metal foil and the surface of the transfer roller during the transfer process, and effectively meeting the requirement of the appropriate peeling strength between the metal foil and the carrier during the application process. At the same time, the water contact angle Y of the first surface of the carrier is also within a reasonable range, so that the outer surface of the carrier has excellent hydrophobicity, which can effectively prevent pollutants such as moisture in the air from adsorbing on the outer surface of the carrier, resulting in the surface of the carrier being wet and oxidized by air, and then reducing or losing the protection and loading functions for the metal foil, leading to problems such as oxidation, wrinkling, and blistering on the surface of the metal foil, which seriously affects the quality of the metal foil.

[0065] As a preferred embodiment, the roughness Rz of the second surface is 0.9 - 1.5 μm.

[0066] In the embodiment of the present invention, on the basis of any of the above embodiments, the roughness Rz of the second surface 12 is set to be between 0.9 and 1.5 μm. For example, it can be 0.9 μm, 0.92 μm, 0.95 μm, 0.97 μm, 1 μm, 1.1 μm, 1.2 μm, 1.21 μm, 1.25 μm, 1.3 μm, 1.35 μm, 1.4 μm, 1.45 μm or 1.5 μm. Of course, the specific value of the roughness Rz of the second surface 12 can be set according to actual usage requirements and will not be elaborated further here. By reasonably optimizing the roughness Rz of the second surface, the roughness of this surface is controlled not to be too large, so that the metal foil replicates the rough morphology of the second surface of the carrier and generates a relatively appropriate roughness, which is not too large either, thus avoiding the problem of excessive transmission loss of the metal foil in the application in the field of printed circuit board technology and effectively improving the quality of the metal foil.

[0067] As a preferred embodiment, the water contact angle Y of the first surface is 1.6 - 5 times that of the water contact angle X of the second surface.

[0068] In an embodiment of the present invention, the water contact angle X of the second surface 12 of the carrier is further optimized, and the water contact angle X of the second surface is less than the water contact angle Y of the first surface. The water contact angle Y of the first surface is 1.6 to 5 times that of the water contact angle X of the second surface. When the water contact angle Y of the first surface of the carrier is in the range of 95° to 106°, the water contact angle X of the second surface 12 is determined according to this ratio, so that the second surface 12 of the carrier has a certain hydrophilicity. In the electroplating deposition production scenario of the metal foil, the electroplating deposition process is carried out on the second surface of the carrier, and the electroplating solution is mostly hydrophilic, which can ensure that the electroplating solution is fully flattened on this surface, so that the electroplating solution is in full contact with this surface, improving the uniformity of electroplating and ensuring the quality stability of the metal foil produced by this electroplating in circuit processing.

[0069] As a preferred embodiment, the first surface 11 of the carrier is subjected to a preset roughening treatment process to form a number of roughened particles; wherein, the maximum vertical height of each roughened particle is between 2.5 and 5 μm, and the maximum width of a roughened particle is between 4 and 10 μm.

[0070] The maximum vertical height refers to the vertical distance between the highest point and the root of the roughened particle, and the maximum width refers to the maximum value of the width or diameter of the roughened particle.

[0071] By adopting the technical means of the embodiment of the present invention, through roughening the first surface of the carrier and optimizing the range of the maximum vertical height and the maximum width of each roughened particle, the roughness parameters of the first surface of the carrier meet the requirements, ensuring the quality of the carrier.

[0072] As a preferred embodiment, the thickness of the carrier is 6 to 35 μm.

[0073] The thickness of the carrier is between 6 and 35 μm, for example, it can be 6 μm, 8 μm, 9 μm, 10 μm, 12 μm, 13 μm, 15 μm, 18 μm, 20 μm, 23 μm, 25 μm, 28 μm, 30 μm, 32 μm or 35 μm, etc. Of course, the specific value of the thickness of the carrier can be set according to actual use requirements and will not be elaborated here.

[0074] By adopting the technical means of the embodiment of the present invention, the carrier has a certain thickness, and in cooperation with the structure set by the roughness and the water contact angle of the carrier, it can effectively improve the quality of the carrier and better realize the loading and protection of the metal foil.

[0075] An embodiment of the present invention provides a carrier for a metal foil, including opposite first and second surfaces, where the roughness Rz of the first surface is greater than the roughness Rz of the second surface; the roughness Rz of the first surface is greater than the roughness Rz of the second surface, and the roughness Rz of the first surface and the water contact angle Y of the first surface satisfy the following functional relationship: Y = -24.152×Rz 2 +270.39×Rz - 649.43, Rz > 0, Y ≥ 90°, such that the outer surface of the carrier of the metal foil has good hydrophobicity. During application, the outer surface of the carrier is not easily contaminated by objects such as moisture and dust in the air, can maintain a relatively dry and clean surface state, and is not easily oxidized. When the carrier is used as a carrier for the metal foil, if the surface of the carrier is easily oxidized, it is difficult to provide good protection for the key material layer in the metal foil. For example, when the metal foil is in a high-temperature lamination process, due to the high hardness of the oxidation points on the carrier, pits and protrusions are formed on the surface of the extremely thin metal layer during the lamination process, resulting in an uneven surface of the extremely thin metal layer. In subsequent applications, it may lead to relatively large line transmission losses, and may also cause poor adhesion when the metal layer is laminated with an application carrier such as a circuit board, resulting in problems such as skewing, blistering, and wrinkling of the metal layer. In addition, it is also possible that the oxidation points fall off during the lamination process and adhere to the surface of the press platen, contaminating the press and thus affecting the subsequent lamination process. However, the carrier of the embodiment of the present invention can maintain a dry, clean, and intact state, can better carry and protect the metal foil, simplifies the environmental requirements for the transportation, storage, etc. of the metal foil, reduces the contamination of the metal foil, and saves the cleaning process before application. At the same time, when the carrier is recycled, the surface in contact with the outside air has good hydrophobicity, which can further simplify the subsequent reuse process and improve the recovery rate of the carrier.

[0076] Example 2

[0077] As a preferred embodiment, refer to Figure 3 , which is a schematic structural diagram of the first metal foil provided by an embodiment of the present invention. The metal foil includes a carrier 1 and a metal layer 2. Among them, the carrier 1 is the carrier 1 provided by any of the above embodiments, that is, the carrier 1 includes opposite first and second surfaces 11 and 12, and the roughness Rz of the first surface is greater than the roughness Rz of the second surface; the roughness Rz of the first surface is greater than the roughness Rz of the second surface, and the roughness Rz of the first surface and the water contact angle Y of the first surface satisfy the following functional relationship: Y = -24.152×Rz 2 +270.39×Rz - 649.43, Rz > 0, Y ≥ 90°, and the correlation coefficient R of the functional relationship2 is 0.9915; and, the first surface 11 of the carrier 1 is the surface on the side away from the metal layer 2, and the second surface 12 of the carrier 1 is the surface on the side close to the metal layer 2.

[0078] Preferably, the metal layer 2 is formed on the second surface of the above-mentioned carrier 1 by means of vacuum sputtering, evaporation plating, electroplating or the like.

[0079] Preferably, the material of the carrier includes at least one of the following metal elements: copper, aluminum, zinc, nickel, chromium, iron, silver and gold; or, the material of the carrier is an organic film.

[0080] In the embodiment of the present invention, the metal foil is a multi-layer structure, including a metal layer 2 and a carrier 1 stacked in sequence. The carrier 1 is used to carry and protect the metal layer 2 so that the metal layer 2 is not damaged by external contact, collision, etc. After the metal foil is hot-pressed with the circuit board, the carrier 1 needs to be peeled off.

[0081] The carrier 1 is separated from the carrier 1 in a peelable removal manner or a non-peelable removal manner. When the carrier 1 is removed in a non-peelable removal manner, the non-peeling methods are, for example: laser etching, chemical etching, grinding, plasma removal, etc. When the carrier 1 is removed by peeling, the peeling methods are, for example: manually peeled off directly, or peeled off by means of mechanical equipment.

[0082] Preferably, the metal layer 2 is an ultra-thin metal layer, and the side of the metal layer 2 away from the carrier 1 is a roughened surface 21 with a certain roughness. It should be noted that the roughness of the roughened surface of the metal layer 2 can be achieved by setting the surface of the metal layer 2 as an uneven surface with undulations, or by setting a number of small protrusions and depressions on the surface of the metal layer 2, or by setting a number of raised roughening particles on the surface of the metal layer 2. Of course, it can also be a combination of at least two of the above three implementation methods, which does not affect the beneficial effects obtained by the present invention.

[0083] As an alternative implementation manner, see Figure 4 , which is a schematic structural diagram of the second metal foil provided by the embodiment of the present invention. The roughened surface 21 has a number of roughening particles 22; and the roughness Rz of the roughened surface 21 is less than or equal to 1.8 μm, preferably 1 - 1.6 μm.

[0084] Adopting this preferred roughness can ensure good substrate adhesion strength while reducing the occurrence of skin effect and reducing the loss of line transmission signals.

[0085] Preferably, the material of the metal layer includes at least one of metal elements such as copper, aluminum, zinc, nickel, silver, titanium, gold, chromium, and cobalt and / or an alloy of at least one of them; and the thickness of the metal layer is 1-5 μm, preferably 1.5-4.5 μm.

[0086] Using the ultra-thin metal layer with this preferred thickness broadens its applications, making it convenient to be applied in special applications such as fine circuits, and at the same time it can also be applied in ordinary circuits, reducing costs, reducing the weight for smart devices, and better meeting the design and application requirements of current smart devices.

[0087] In the embodiment of the present invention, in actual applications, such as when applied in the field of circuit boards, the metal layer 2 is thermally pressed and bonded to the substrate of the circuit board. And for example, when applied in the field of batteries, the metal foil serves as the negative electrode material of the battery, and the metal layer 2 is thermally pressed and bonded to the negative electrode active material in the negative electrode material. The side of the metal layer 2 for bonding to materials such as the substrate of the circuit board or the negative electrode active material is set as the roughened surface 21, thereby increasing the adhesiveness of the metal layer 2 and reducing the occurrence of blistering, wrinkling, cracking, etc. during bonding.

[0088] The metal layer 2 is composed of a metal with good conductivity and low resistivity. The constituent materials of the metal layer 2 include single metals and / or alloys; among them, the single metal is made of any one of copper, aluminum, zinc, nickel, silver, titanium, gold, chromium, and cobalt, and the alloy is made of any two or more of copper, aluminum, zinc, nickel, silver, titanium, gold, chromium, and cobalt, or can also be made by mixing any two or more of the above materials with other materials.

[0089] In the specific implementation process, the metal layer 2 of the metal foil can be formed first, and then roughened particles 22 can be formed on one side surface of the metal layer 2 through other processes. Of course, the metal layer 2 of the metal foil and the roughened particles 22 can also be an integral structure formed by a one-step forming process. It should be noted that the material of the roughened particles 22 can be the same as the material of the metal layer 2, or partially the same or different, and is not limited herein.

[0090] Preferably, referring to Figure 5 , it is a schematic structural diagram of the third metal foil provided by the embodiment of the present invention. The metal foil includes a carrier 1 and a metal layer 2, and further includes a release layer 3. The release layer 3 is disposed between the carrier 1 and the metal layer 2, that is, the metal foil includes the carrier 1, the release layer 3, and the metal layer 2 stacked in sequence. And the side of the carrier 1 away from the release layer 3 is the first surface 11, the side of the carrier 1 close to the release layer 3 is the second surface 12, and the side of the metal layer 2 away from the release layer 3 is the roughened surface 21.

[0091] In an embodiment of the present invention, when the carrier 1 is removed by peeling, the peeling method is: removing it by peeling the peeling layer 3, that is, separating the carrier 1 from the metal layer 2 by peeling the peeling layer 3.

[0092] Meanwhile, due to the existence of the peeling layer, metal migration between the metal layer 2 and the carrier 1 can be blocked. Moreover, the peeling layer 3 can cover or fill the uneven surface of the carrier 1 to a certain extent, making the metal layer 2 formed on the other surface of the peeling layer 3 smoother, more uniform, and denser, reducing the occurrence of pinholes, and thus being beneficial to the subsequent circuit fabrication.

[0093] Preferably, the peeling layer 3 is made of a metal material or a non-metal material. The metal materials include any one or more of zinc, nickel, cadmium, copper, molybdenum, titanium, and niobium; the non-metal materials include oxygen, silicon, graphite, organic polymer materials, etc. When the peeling layer is a non-metal material, the form can be 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. Among them, the release layer can be formed by coating 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, etc. When using the above two release agents, the mass ratio of HDPE∶PMA is preferably (1 - 5)∶7. In another embodiment, the release agent can include a fluorine-based release agent and a solvent; among them, the volume ratio of the fluorine-based release agent∶solvent is preferably (5 - 30)∶1. It can be understood that the types of the above solvents are not particularly limited, and conventional release agent solvents in the art can be selected, such as methyl ethyl ketone, which do not constitute a limitation to the present invention.

[0094] Preferably, when the material of the peeling layer 3 is a metal material, the thickness of the peeling layer is 2 - 100 nm; or, when the material of the peeling layer is a non-metal material, the thickness of the peeling layer is less than or equal to 1 μm. The specific thickness of the peeling layer 3 can be set according to actual usage requirements and will not be elaborated further here.

[0095] Adopting the structural setting of the peeling layer in the invention embodiment can ensure appropriate adhesion strength. At the same time, it also retains a certain adhesion ability, so that the metal foil will not delaminate during the hot pressing process.

[0096] As a preferred implementation manner, in the metal foil, a medium for heat absorption is filled in the carrier 1 and / or the peeling layer 3. By adding the medium for heat absorption, when the metal foil is hot pressed onto the circuit board substrate or hot press bonded as the negative electrode material of a new energy battery with the negative electrode active material, the medium for heat absorption can absorb heat, reducing the heat of the bonding surface of the metal layer 2, and further reducing the occurrence of blistering, wrinkling, cracking, etc. during the bonding of the metal foil.

[0097] Preferably, the medium for heat absorption is filler particles.

[0098] See Figures 6 to 8 , which is a schematic structural diagram of the fourth to sixth metal foils provided by the embodiments of the present invention. In the metal foil, there are three ways to fill the filler particles: one is to fill the first filler particles 13 only in the carrier 1, and specifically, reference can be made to Figure 6 ; the second is to fill the second filler particles 31 only in the release layer 3, and specifically, reference can be made to Figure 7 ; the third is to fill the first filler particles 13 in the carrier 1 and fill the second filler particles 31 in the release layer 3, and specifically, reference can be made to Figure 8 .

[0099] It can be understood that Figures 6 to 8 the shape of the filler particles in

[0100] is merely exemplary. Due to differences in process means and parameters, the filler particles can also be in other shapes such as cluster shape, icicle shape, stalactite shape, dendritic shape, etc. In addition, the medium for heat absorption in the embodiments of the present invention is not limited to filler particles, nor is it limited by the illustrations and the above shapes. As long as the medium is filled in the carrier or the release layer and has a heat absorption effect, it is within the protection scope of the present invention. Figure 9 , which is a schematic structural diagram of the seventh metal foil provided by the embodiments of the present invention. The metal foil includes a metal layer 2, a carrier 1, and a release layer 3, and further includes an adhesive layer 4, and the adhesive layer 4 is provided between the carrier 1 and the release layer 3. That is, the metal foil includes the carrier 1, the adhesive layer 4, the release layer 3, and the metal layer 2 stacked in sequence, and the surface of the metal layer 2 away from the release layer 3 is the roughened surface 21.

[0101] By adopting the technical means of the embodiments of the present invention, an adhesive layer 4 is added between the carrier 1 and the release layer 3 to improve the adhesion between the carrier 1 and the release layer 3. When peeling, the two will not separate, and the peeling force increases, which can effectively improve the peeling effect. At the same time, due to the presence of the adhesive layer 4 and the release layer 3, the uneven surface of the carrier 1 can be covered to a certain extent, making the metal layer 2 formed on the other side of the release layer 3 more flat, uniform, and dense, reducing the occurrence of pinholes, which is beneficial to the subsequent circuit production.

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

[0103] As a preferred embodiment, refer to Figure 10 , which is a schematic structural diagram of the eighth metal foil provided by the embodiment of the present invention. The metal foil further includes a first anti-oxidation layer 5, and the first anti-oxidation layer 5 is provided on the surface of the metal layer 2 close to the release layer 3. That is, the metal foil includes a carrier 1, a release layer 3, a first anti-oxidation layer 5, and a metal layer 2 that are sequentially stacked.

[0104] In the embodiment of the present invention, by providing the first anti-oxidation layer 5 between the release layer 3 and the metal layer 2, the anti-oxidation performance of the metal layer 2 can be improved, preventing the formation of an oxide film due to oxidation and affecting the electrical and thermal conductivity effects. At the same time, the number of pinholes on the surface of the metal foil is reduced, ensuring the integrity of the etching line conduction after subsequent bonding to the circuit board substrate. And because the adhesion force between the first anti-oxidation layer 5 and the release layer 3 is weak, the release effect can also be improved.

[0105] Optionally, the first anti-oxidation layer 5 is made of at least one of metals such as nickel, copper, chromium, zinc, etc. and / or an alloy including at least one of them. Exemplarily, the first anti-oxidation layer 5 is formed on the surface of the metal layer 2 through processes including electroless plating, chemical microelectroplating, etc.

[0106] As a preferred embodiment, refer to Figure 11 , which is a schematic structural diagram of the ninth metal foil provided by the embodiment of the present invention. The metal foil further includes a second anti-oxidation layer 6, and the second anti-oxidation layer 6 is provided on the surface of the metal layer 2 away from the release layer 3. That is, the metal foil includes a carrier 1, a release layer 3, a first anti-oxidation layer 5, a metal layer 2, and a second anti-oxidation layer 6 that are sequentially stacked.

[0107] In the embodiment of the present invention, by adding the second anti-oxidation layer 6 on the roughened surface 21 of the metal layer 2, the anti-oxidation property of the bonding surface between the metal layer 2 and the circuit board substrate can be effectively protected, and by selecting a suitable material, the bonding performance between the metal layer 2 and the substrate can be synergistically improved.

[0108] Optionally, the second anti-oxidation layer 6 is made of at least one of metals such as nickel, copper, chromium, zinc, etc. and / or an alloy of at least one of them. Exemplarily, the second anti-oxidation layer 6 is formed on the roughened surface 21 of the metal layer 2 through processes including electroless plating, chemical microelectroplating, etc.

[0109] As a preferred embodiment, referring to Figure 12 , it is a schematic structural diagram of the tenth metal foil provided by the embodiment of the present invention. The metal foil further includes a resin layer 7, and the resin layer 7 is disposed on the surface of the metal layer 2 away from the release layer 3. That is, the metal foil includes a carrier 1, a release layer 3, a metal layer 2, and a resin layer 7 that are sequentially stacked.

[0110] In the embodiment of the present invention, adding a resin layer 7 on the roughened surface 21 of the metal layer 2, that is, setting a resin layer 7 on the surface where the metal layer 2 is bonded to the circuit board substrate, can not only achieve functions such as anti-oxidation, moisture-proof, and waterproof, but also improve the bonding performance with the substrate.

[0111] The resin layer 7 is made of at least one of thermoplastic resin, thermosetting resin, BT resin, and ABF resin. Among them, thermoplastic resin includes polystyrene-based, vinyl acetate-based, polyester-based, polyethylene-based, polyamide-based, rubber-based, or acrylate-based thermoplastic resin; thermosetting resin includes phenolic-based, epoxy-based, thermoplastic polyimide, urethane-based, melamine-based, or alkyd-based thermosetting resin.

[0112] It should be noted that the structure of the metal foil provided by the embodiment of the present invention is not limited to the multi-layer structure of the above embodiment. In actual applications, other material layers and additional structures can also be added according to requirements, which do not constitute a limitation to the present invention.

[0113] By adopting the technical means of the embodiment of the present invention, the metal foil adopts a multi-layer structure. Among them, the carrier includes opposite first surface and second surface. By optimizing the relationship between the roughness Rz of the opposite two surfaces of the carrier, the roughness of the first surface, and the water contact angle, the outer surface of the carrier has good hydrophobicity. The hydrophobic surface can well overcome various adverse problems caused by the adsorption of pollutants such as moisture in the air on the outer surface of the carrier, such as the surface moisture and air oxidation of the carrier, and cooperate with other multi-layer structures of the metal foil to effectively improve the various performances and quality of the metal foil.

[0114] In the embodiment of the present invention, the test methods for the roughness Rz and the water contact angle Y of the first surface of the carrier of the metal foil are specifically as follows:

[0115] Cut the metal foil sample into a size of 100mm×150mm, and use a contact roughness tester or a white light interferometer to measure the roughness of the first surface of the carrier of the metal foil sample, denoted as roughness Rz. And use a water contact angle testing device to test the water contact angle value of the first surface of the carrier, and denote it as water contact angle Y.

[0116] Specific examples were used to test the oxidation rate, scrap rate after high-temperature lamination, and recycling rate of the first surface of the carrier of the ordinary metal foil and the metal foil of the structure of the embodiment of the present invention respectively; among them,

[0117] A represents the metal foil product of the embodiment of the present invention, including randomly selected sample metal foils A1, A2, A3, and A4;

[0118] B is a commercially available ordinary metal foil product.

[0119] The test data and comparison results are shown in Table 1:

[0120] Table 1

[0121]

[0122]

[0123] Among them, the surface oxidation rate of the metal foil refers to randomly taking 10 copies of each sample, and after a certain period of time under the same storage conditions, calculating the oxidized samples that have oxidized, and / or the percentage of the number of oxidation points on the oxidized samples among these 10 samples.

[0124] It can be seen that compared with the ordinary metal foil sold on the market, the metal foil with the structure of the embodiment of the present invention has a lower oxidation rate on the outer surface of the carrier, a lower scrap rate after the same high-temperature lamination process, and a higher recovery rate, and all performances are better than those of ordinary commercially available products.

[0125] Example 3

[0126] The embodiment of the present invention provides a circuit board, the circuit board includes a circuit board substrate 9 and the metal foil as described in any one of the above embodiments; the metal foil includes a carrier 1 and a metal layer 2, and the side of the metal layer 2 away from the carrier 1 is pressed against the circuit board substrate.

[0127] It should be noted that the structure of the metal foil can refer to the structure of the metal foil described in any one of the above embodiments, and will not be elaborated here.

[0128] By adopting the technical means of the embodiments of the present invention, through optimizing the relationship among the roughness Rz of the opposite two surfaces of the carrier of the metal foil, the roughness Rz of the first surface, and the water contact angle, the outer surface of the carrier has good hydrophobicity, is not easily affected by contaminants such as moisture and fine particles in the air, and is not easily oxidized. It can maintain a relatively dry, clean and intact surface state, thereby playing a good role in protecting and carrying the metal foil, being applicable to the production of high-frequency and high-density circuit boards, and being able to avoid problems such as pits and protrusions on the surface of the extremely thin metal foil during hot pressing due to the high hardness of the oxidation points of the carrier, and even causing wrinkles and blisters of the extremely thin metal foil due to the rupture of the carrier from the oxidation points. This simplifies the environmental requirements for the transportation and storage of the metal foil and improves the quality of the metal foil.

[0129] Example 4

[0130] The embodiments of the present invention also provide a copper-clad laminate, specifically a flexible copper-clad laminate (FCCL), also known as a flexible copper-clad laminate. The flexible copper-clad laminate includes the metal foil described in any of the above embodiments.

[0131] 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, which will not be elaborated here.

[0132] The structure of the flexible copper-clad laminate includes: a metal foil layer, an adhesive layer, a metal foil layer, or includes: a metal foil layer, an adhesive layer. The material of the adhesive layer can be polyimide (PI), thermoplastic polyimide (TPI), resin, etc.

[0133] Compared with the prior art, the application of the metal foil with an improved carrier as the material of the above flexible copper-clad laminate has the following advantages: By optimizing the relationship among the roughness Rz of the opposite two surfaces of the carrier of the metal foil, the roughness Rz of the first surface, and the water contact angle, the outer surface of the carrier has good hydrophobicity, is not easily affected by contaminants such as moisture and fine particles in the air, and is not easily oxidized. It can maintain a relatively dry, clean and intact surface state, thereby playing a good role in protecting and carrying the metal foil, avoiding affecting the various properties of the metal foil, improving the yield of the manufactured copper-clad laminate products, making the performance of the products more stable and reliable during subsequent specific use, having less high-frequency signal transmission loss, and reducing production costs.

[0134] In addition, the copper-clad laminate can also be a resin-coated copper foil (RCC), which is mainly used for high-density circuits. At this time, the roughened surface of the metal foil is away from the side where the copper foil is coated with resin.

[0135] Example 5

[0136] An embodiment of the present invention also provides a semiconductor material, which includes the metal foil described in any of the above embodiments.

[0137] 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 elaborated here.

[0138] By adopting the technical means of the embodiment of the present invention, when the metal foil is used as an application of the semiconductor material, by optimizing the relationship between the roughness Rz of the two opposite surfaces of the carrier of the metal foil, the roughness Rz of the first surface, and the water contact angle, the outer surface of the carrier has good hydrophobicity, is not easily affected by contaminants such as moisture and fine particles in the air, and is not easily oxidized. It can maintain a relatively dry, clean and intact surface state, thereby playing a good protection and loading function for the metal foil, avoiding affecting the various properties of the metal foil, improving the quality of the metal foil product, being 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.

[0139] Example 6

[0140] An embodiment of the present invention also provides a negative electrode material for a battery, which includes the metal foil described in any of the above embodiments.

[0141] 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 elaborated here.

[0142] An embodiment of the present invention also provides a battery, the negative electrode material of which includes the metal foil described in any of the above embodiments.

[0143] Compared with the prior art, when the metal foil is used as the negative electrode carrier or current collector of the above battery, it has the following advantages: By optimizing the relationship between the roughness Rz of the two opposite surfaces of the carrier of the metal foil, the roughness Rz of the first surface, and the water contact angle, the outer surface of the carrier has good hydrophobicity, is not easily affected by contaminants such as moisture and fine particles in the air, and is not easily oxidized. It can maintain a relatively dry, clean and intact surface state, thereby playing a good protection and loading function for the metal foil, avoiding affecting the various properties of the metal foil, improving the quality of the metal foil product. Furthermore, it is beneficial for the metal foil to be applied to new energy batteries and improve the service life and safety of new energy batteries. The metal foil can be applied to the negative electrode materials of new energy batteries, such as lithium-ion batteries and sodium-ion batteries, as the negative electrode current collector and carrier material.

[0144] The above are the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements are also regarded as the protection scope of the present invention.

Claims

1. A carrier for a metal foil, characterized in that, The carrier includes opposite first and second surfaces. The roughness Rz of the first surface is greater than that of the second surface, and the roughness Rz of the first surface and the water contact angle Y of the first surface satisfy the following functional relationship: Y = -24.152×Rz 2 +270.39×Rz - 649.43, where Rz > 0, Y ≥ 90°, and the function The correlation coefficient R of the numerical relationship 2 is 0.9915.

2. The carrier of the metal foil according to claim 1, characterized in that, The water contact angle Y of the first surface is 95° to 106°.

3. The carrier of the metal foil according to claim 1, characterized in that, The roughness Rz of the first surface is 2.8 to 5 μm.

4. The carrier of the metal foil according to claim 1, characterized in that, The root mean square roughness Rq of the first surface is 0.6 to 1.3 μm.

5. The carrier of the metal foil according to any one of claims 1 to 4, characterized in that The roughness Rz of the second surface is 0.9 to 1.5 μm.

6. The carrier of the metal foil according to claim 2, characterized in that The water contact angle Y of the first surface is 1.6 to 5 times that of the water contact angle X of the second surface.

7. The carrier of the metal foil according to claim 1, characterized in that, The thickness of the carrier is 6 to 35 μm.

8. A metal foil, characterized in that, A carrier including a metal layer and the metal foil as claimed in claim 1, wherein the first surface of the carrier is the surface on the side away from the metal layer, and the second surface of the carrier is the surface on the side close to the metal layer.

9. The metal foil according to claim 8, wherein The material of the carrier includes at least one of the following metal elements: copper, aluminum, zinc, nickel, chromium, iron, silver, and gold; or, the material of the carrier is an organic film.

10. The metal foil according to claim 8, wherein, The surface of the metal layer away from the carrier is a roughened surface, and the roughened surface has a number of roughened particles; and the roughness Rz of the roughened surface is less than or equal to 2 μm.

11. The metal foil according to claim 10, characterized in that, The material of the metal layer includes single metal and / or alloy; wherein, the single metal is made of any one of copper, aluminum, zinc, nickel, silver, titanium, gold, chromium, and cobalt, and the alloy includes any two or more of copper, aluminum, zinc, nickel, silver, titanium, gold, chromium, and cobalt; and the thickness of the metal layer is 1 to 5 μm.

12. The metal foil according to claim 8, wherein The metal foil further includes a release layer, the release layer is disposed between the carrier and the metal layer, and the thickness of the release layer is 1 to 8 nm.

13. A circuit board, characterized in that, Including a printed circuit board substrate and the metal foil as claimed in any one of claims 8 to 12; the surface of the metal layer away from the carrier is pressed against the printed circuit board substrate.

14. A copper-clad laminate, characterized in that, The copper-clad laminate includes the metal foil as claimed in any one of claims 8 to 12.

15. A semiconductor material, characterized in that, The semiconductor material includes the metal foil as claimed in any one of claims 8 to 12.

16. A negative electrode material applied to a battery, characterized in that, The negative electrode material includes the metal foil as claimed in any one of claims 8 to 12.

17. A battery, characterized in that, The negative electrode material of the battery includes the metal foil as claimed in any one of claims 8 to 12.

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