Metal foil and metal-clad laminated plate

Abstract

The invention discloses a metal foil and a metal-clad laminated plate, the metal foil comprises a carrier layer, a stripping layer and a functional layer which are sequentially laminated, the surface of one side, close to the stripping layer, of the carrier layer is a first stripping surface, and the surface of one side, close to the stripping layer, of the functional layer is a second stripping surface; the mean value of the water drop angles of the first stripping surface and / or the second stripping surface is greater than or equal to 100 degrees. According to the invention, the stripping part between the carrier layer and the functional layer can be ensured to be a hydrophobic interface, so that liquid medicine permeation can be effectively avoided in wet processes such as electroplating, etching and the like in an ETS / core process, additional edge sealing or improvement of the binding force between the carrier layer and the functional layer is not needed, and the effect that the carrier layer and the functional layer are not damaged after multiple times of pressing is ensured. The functional layer and the carrier layer can be smoothly stripped during board separation, so that the production yield is effectively improved, and meanwhile, the production cost is prevented from being increased due to the increase of production procedures.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic information materials, in particular to a metal foil and a metal-clad laminate. Background Art

[0002] Peelable metal foil with a carrier is widely used for lamination with substrates through hot pressing. When using ETS (Embedded Trace Substrate) and coreless processes to produce ultra-fine circuits, one side of a carrier layer (such as a carrier copper layer) is first pressed onto the substrate at high temperature. The functional layer (such as a thin copper layer) and the carrier layer are then subjected to wet processes such as electroplating and etching. After multiple press cycles, a multilayer board is formed. Finally, the functional layer and carrier layer must be separated between the boards to complete the depaneling.

[0003] In wet processes such as electroplating and etching of peelable metal foil, chemicals can easily seep into the space between the functional layer and the carrier layer, causing product defects. In order to prevent chemicals from seeping into the space between the functional layer and the carrier layer, existing metal foils usually require a strong bonding force between the functional layer and the carrier layer, or perform edge sealing through electroplating or other methods. However, if the bonding force between the functional layer and the carrier layer is strong, it is easy to cause the functional layer and the carrier layer to be difficult to peel apart when depaneling after multiple pressings; and edge sealing through electroplating or other methods will increase the production process and increase production costs. Summary of the Invention

[0004] The present invention provides a metal foil and a metal-clad laminate, which can effectively prevent the infiltration of chemicals during wet processes such as electroplating and etching in the ETS / coreless process without the need for additional edge sealing or improving the bonding strength between the carrier layer and the functional layer, thereby effectively improving the production yield and avoiding the increase in production costs due to the increase in production steps.

[0005] In order to solve the above technical problems, the first aspect of an embodiment of the present invention provides a metal foil, comprising a carrier layer, a peeling layer and a functional layer stacked in sequence, wherein the surface of the carrier layer close to the peeling layer is a first peeling surface, and the surface of the functional layer close to the peeling layer is a second peeling surface; the average water drop angle of the first peeling surface and / or the second peeling surface is greater than or equal to 100°.

[0006] As a preferred solution, the mean value of the water drop angle is the average value of the water drop angles of M test points randomly selected from the first peeling surface and / or the second peeling surface; wherein M is a positive integer greater than or equal to 10.

[0007] As a preferred solution, the difference between the maximum water drop angle and the minimum water drop angle among the water drop angles at the M test points is less than or equal to 5°.

[0008] As a preferred embodiment, the first peeling surface and / or the second peeling surface has a hydrophobic material layer formed by sputtering or electroplating;

[0009] Alternatively, two opposite surfaces of the release layer are provided with a hydrophobic material layer formed by sputtering or electroplating.

[0010] As a preferred solution, the hydrophobic material layer includes silicon dioxide and fluorosilane.

[0011] As a preferred solution, the peeling force between the functional layer and the carrier layer is 0.05 N / cm to 0.6 N / cm.

[0012] As a preferred solution, after N times of lamination, the peeling force between the functional layer and the carrier layer is less than or equal to 0.8 N / cm; wherein N is a positive integer greater than or equal to 5.

[0013] As a preferred solution, the peeling layer is made of an organic material, an inorganic material or a mixed material; wherein the mixed material includes the organic material and the inorganic material.

[0014] As a preferred solution, an anti-oxidation layer is further included, and the anti-oxidation layer is arranged on a surface of the functional layer away from the peeling layer.

[0015] A second aspect of the embodiments of the present invention provides a metal-clad laminate, wherein the metal-clad laminate is made of the functional layer in the metal foil as described in any one of the first aspects as one of the materials.

[0016] Compared with the prior art, the beneficial effect of the embodiments of the present invention is that by limiting the average water drop angle of the first peeling surface on the carrier layer in contact with the peeling layer and / or the second peeling surface on the functional layer in contact with the peeling layer to be greater than or equal to 100°, it is possible to ensure that the peeling point between the carrier layer and the functional layer is a hydrophobic interface, thereby effectively avoiding the penetration of chemicals during wet processes such as electroplating and etching in the ETS\coreless process, and there is no need for additional edge sealing or increasing the bonding strength between the carrier layer and the functional layer, ensuring that after multiple pressings, the functional layer and the carrier layer can be smoothly peeled off when the boards are separated, effectively improving the production yield, and avoiding the increase in production costs due to the increase in production processes. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a flow diagram of the ETS\coreless process;

[0018] Figure 2 1 is a schematic structural diagram of a first metal foil according to an embodiment of the present invention;

[0019] Figure 3Schematic diagram of the structure of the second metal foil in an embodiment of the present invention;

[0020] Figure 4 1 is a schematic structural diagram of a third metal foil in an embodiment of the present invention;

[0021] Figure 5 1 is a schematic structural diagram of a fourth metal foil according to an embodiment of the present invention;

[0022] Figure 6 1 is a schematic structural diagram of a fifth metal foil according to an embodiment of the present invention;

[0023] Among them, 1. carrier layer; 2. peeling layer; 3. functional layer; 4. first peeling surface; 5. second peeling surface; 6. hydrophobic material layer; 7. anti-oxidation layer. DETAILED DESCRIPTION

[0024] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. The purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0025] In the description of this application, the terms "first," "second," "third," etc. are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, a feature specified as "first," "second," "third," etc. may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise specified, "plurality" means two or more.

[0026] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be a communication between the two components. The terms "vertical", "horizontal", "left", "right", "up", "down" and similar expressions used herein are for illustrative purposes only, and do not indicate or imply that the device or component referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0027] In the description of this application, it should be noted that, unless otherwise defined, all technical and scientific terms used in this application have the same meanings as those commonly understood by those skilled in the art. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood by those skilled in the art in specific circumstances.

[0028] See also Figure 1 The ETS\coreless process flow is as follows: ① Laminating a peelable metal foil with a carrier on both sides of the substrate, wherein the carrier layer (such as a carrier copper layer) is laminated on the substrate; ② Covering the surface of the functional layer (such as a thin copper layer) on both sides with a mask, and etching the functional layer not protected by the mask to form a circuit; ③ Laminating the substrate and the peelable metal foil with a carrier on the circuits on both sides again for stacking; ④ Peeling off the outermost carrier layer and plating holes to achieve electrical connection between different layers; ⑤ Laminating the substrate and the peelable metal foil with a carrier on both sides again for stacking; ⑥ After peeling off the outermost carrier layer, covering the surface of the outermost functional layer with a mask, and etching the functional layer not protected by the mask to form a circuit; ⑦ Separating the carrier layer and the functional layer on both sides of the middle substrate for de-boarding to obtain a multi-layer laminated board on both sides; ⑧ Biting off the surface bottom copper by flash etching; ⑨ Finally, applying ink.

[0029] In the wet processes such as electroplating and etching in the above-mentioned ETS\coreless process, chemicals easily penetrate between the functional layer (such as the thin copper layer) and the carrier layer (such as the carrier copper layer). The present invention further proposes a metal foil to solve this problem.

[0030] See also Figure 2 In a first aspect of an embodiment of the present invention, a metal foil is provided, comprising a carrier layer 1, a peeling layer 2, and a functional layer 3 stacked in sequence, wherein a surface of the carrier layer 1 close to the peeling layer 2 is a first peeling surface 4, and a surface of the functional layer 3 close to the peeling layer 2 is a second peeling surface 5; an average water drop angle of the first peeling surface 4 and / or the second peeling surface 5 is greater than or equal to 100°.

[0031] It is worth noting that, in actual use, the carrier layer 1 is stacked with other material layers in the metal foil, such as the functional layer 3, to support and protect the functional layer 3, thereby preventing the functional layer 3 from being damaged by external contact or collision, or to meet the requirements of more sophisticated circuit manufacturing processes. In this embodiment, the material of the carrier layer 1 can include any one of aluminum, titanium, zinc, iron, nickel, chromium, cobalt, copper, silver, and gold, and this embodiment is not specifically limited here.

[0032] The functional layer 3 plays a conductive role. The material of the functional layer 3 may include any one of aluminum, titanium, zinc, iron, nickel, chromium, cobalt, copper, silver and gold, which will not be described in detail in this embodiment.

[0033] The function of the peeling layer 2 is to separate the carrier layer 1 and the functional layer 3 by peeling. At the same time, due to the presence of the peeling layer 2, the metal migration between the functional layer 3 and the carrier layer 1 can be blocked. Moreover, the peeling layer 2 can cover or fill the uneven surface of the carrier layer 1, making the functional layer 3 formed on the other surface of the peeling layer 2 more flat, uniform and dense, reducing the occurrence of pinholes, and thus facilitating the subsequent circuit production.

[0034] In this embodiment, in order to effectively prevent the infiltration of chemical solutions during wet processes such as electroplating and etching in the ETS\coreless process, the average water drop angle of the first release surface 4 on the carrier layer 1 that contacts the release layer 2 and / or the second release surface 5 on the functional layer 3 that contacts the release layer 2 is limited to be greater than or equal to 100°. For example, the average water drop angle of the first release surface 4 and / or the second release surface 5 can be 100°, 106°, 110°, 114°, 121°, 129°, 130°, 138°, 145°, 150°, 160°, 170°, 175°, etc., which are not specifically limited in this embodiment. It is worth noting that when a liquid is dropped on a solid surface, the liquid forms a droplet on the solid surface. The angle between the edge of the droplet and the solid surface is the water drop angle. The size of the water drop angle can reflect the interaction between the liquid and the solid. For solid surfaces with a water drop angle greater than 90°, the larger the water drop angle, the more hydrophobic the solid surface is, and the more difficult it is for the droplet to spread on the solid surface; for solid surfaces with a water drop angle less than 90°, the smaller the water drop angle, the more hydrophilic the solid surface is, and the better the droplet can spread on the solid surface. Therefore, by limiting the average value of the water drop angle of the first peeling surface 4 and / or the second peeling surface 5 to be greater than or equal to 100°, the water drop angle at each position on the first peeling surface 4 and / or the second peeling surface 5 is large, so as to ensure that the peeling point between the carrier layer 1 and the functional layer 3 is a hydrophobic interface. Therefore, during wet processes such as electroplating and etching in the ETS\coreless process, it is difficult for the chemical to spread at the peeling point between the carrier layer 1 and the functional layer 3, effectively avoiding the infiltration of the chemical. At the same time, since there is no need for additional edge sealing or increasing the bonding force between the carrier layer 1 and the functional layer 3, it is possible to avoid the bonding force between the carrier layer 1 and the functional layer 3 being too high, so that the functional layer 3 and the carrier layer 1 will not be pulled and deformed due to difficulty in peeling when the panels are separated, thereby effectively improving the production yield and avoiding an increase in production costs due to an increase in production processes.

[0035] It is worth noting that in this embodiment, the average water drop angle of only the first peeling surface 4 can be greater than or equal to 100°, or the average water drop angle of only the second peeling surface 5 can be greater than or equal to 100°, or the average water drop angle of both the first peeling surface 4 and the second peeling surface 5 can be greater than or equal to 100° at the same time, wherein the average water drop angle of the first peeling surface 4 and the average water drop angle of the second peeling surface 5 can be equal or unequal, and this embodiment does not make any specific limitations here.

[0036] As a preferred solution, the mean water drop angle is the average value of the water drop angles of M test points randomly selected from the first peeling surface 4 and / or the second peeling surface 5; wherein M is a positive integer greater than or equal to 10.

[0037] Specifically, in this embodiment, the mean water drop angle value for the peeling surface is obtained as follows: M test points are randomly selected on the first peeling surface 4 and / or the second peeling surface 5 for water drop angle testing, thereby obtaining M water drop angles. These M water drop angles are then averaged, and the obtained average value is the mean water drop angle value for the current peeling surface. Preferably, when performing the water drop angle test, the peeling surface can be divided into multiple sampling areas, with the multiple sampling areas spaced evenly apart. At least one test point is selected within each sampling area to achieve dispersed sampling of the water drop angle on the peeling surface. This reduces the error in the mean water drop angle value obtained through testing.

[0038] Furthermore, in this embodiment, the water drop angle at each test point is obtained by testing with a water drop angle meter. The test of the water drop angle complies with the ISO 19403 standard. Preferably, an optical water drop angle meter is used and the Young-Laplace fitting method is adopted to obtain the optimal test accuracy. The Young-Laplace fitting method is a method of inferring the water drop angle through mathematical fitting of the droplet profile. It has high accuracy and is particularly suitable for testing scenarios where the water drop angle is greater than 90° or non-axisymmetric droplets.

[0039] Furthermore, in this embodiment, the number of test points M on the peeling surface is a positive integer greater than or equal to 10. For example, the number of test points M can be 10, 12, 14, 16, 18, 20, 24, 28, 30, etc. This embodiment does not make specific limitations here, so as to ensure that the number of test points is large enough to ensure that the water drop angles at multiple positions on the peeling surface are tested, and to ensure that the water drop angles are dispersed in multiple tests, thereby improving the accuracy of the final calculated average water drop angle.

[0040] As a preferred solution, the difference between the maximum water drop angle and the minimum water drop angle among the water drop angles at the M test points is less than or equal to 5°.

[0041] Specifically, the embodiment further limits the difference between the maximum water droplet angle and the minimum water droplet angle in the water droplet angles of the M test points to be less than or equal to 5°, for example, the difference between the maximum water droplet angle and the minimum water droplet angle can be 0.5°, 1°, 1.5°, 2°, 2.5°, 3°, 3.5°, 4°, 4.5°, 5°, etc., which is not limited herein. It is worth noting that by limiting the range of the water droplet angles of the M test points to be within 5°, the hydrophobic performance of the whole peeling surface can be more uniform, thereby ensuring that the peeling between the carrier layer 1 and the functional layer 3 can effectively avoid the infiltration of the chemical liquid in all directions during the wet processes such as electroplating and etching in the ETS / coreless process.

[0042] As a preferred solution, the first peeling surface 4 and / or the second peeling surface 5 has a hydrophobic material layer 6 formed by sputtering or electroplating;

[0043] Alternatively, the opposite two side surfaces of the peeling layer 2 each have a hydrophobic material layer 6 formed by sputtering or electroplating.

[0044] Specifically, in order to form a hydrophobic interface at the peeling between the carrier layer 1 and the functional layer 3, the embodiment adds a layer of hydrophobic material layer 6 to the first peeling surface 4 by sputtering or electroplating, as shown in Figure 3 Alternatively, a layer of hydrophobic material layer 6 is added to the second peeling surface 5 by sputtering or electroplating, as shown in Figure 4 Alternatively, as shown in Figure 5 Alternatively, as shown in

[0045] As a preferred solution, the hydrophobic material layer 6 includes silicon dioxide and fluorosilane.

[0046] Specifically, the hydrophobic materials used to make the hydrophobic material layer 6 in this embodiment include, but are not limited to, silicon dioxide and fluorosilane. It is worth noting that, since both silicon dioxide and fluorosilane have low surface energies, the use of silicon dioxide and / or fluorosilane to make the hydrophobic material layer 6 makes it difficult for water molecules to strongly interact with the hydrophobic material layer 6. The solution in wet processes such as electroplating and etching during the ETS\coreless process is difficult to spread on the surface of the hydrophobic material layer 6, thereby ensuring that the hydrophobic material layer 6 has good hydrophobic properties. In addition to silicon dioxide and fluorosilane, other materials with good hydrophobic properties can also be used as the hydrophobic material for making the hydrophobic material layer 6, such as polytetrafluoroethylene, fluorinated acrylate coatings, silicone-modified acrylate coatings, fluororesin coatings, etc. This embodiment will not be described in detail here.

[0047] As a preferred solution, the peeling force between the functional layer 3 and the carrier layer 1 is 0.05 N / cm to 0.6 N / cm.

[0048] Specifically, if the peeling force between the functional layer 3 and the carrier layer 1 is too large, it will be difficult to peel the carrier layer 1 from the functional layer 3 and the functional layer 3 will be easily damaged. If the peeling force is too small, the functional layer 3 will easily fall off from the carrier layer 1. Therefore, in this embodiment, the peeling force between the functional layer 3 and the carrier layer 1 is limited to 0.05N / cm to 0.6N / cm. For example, the peeling force between the functional layer 3 and the carrier layer 1 can be 0.05N / cm, 0.1N / cm, 0.15N / cm, 0.2N / cm, 0. 25N / cm, 0.3N / cm, 0.35N / cm, 0.4N / cm, 0.45N / cm, 0.5N / cm, 0.55N / cm, 0.6N / cm, etc., which are not specifically limited in this embodiment, so that the carrier layer 1 will not be difficult to peel off from the functional layer 3 due to excessive peeling force, nor will the functional layer 3 easily fall off from the carrier layer 1 automatically due to excessive peeling force, which can effectively ensure the peeling stability of the metal foil and further ensure the production yield of the ETS process and the coreless process.

[0049] As a preferred solution, after N times of lamination, the peeling force between the functional layer 3 and the carrier layer 1 is less than or equal to 0.8 N / cm; wherein N is a positive integer greater than or equal to 5.

[0050] Specifically, considering that during the production process of the ETS process and the coreless process, the metal foil needs to be pressed multiple times before the functional layer 3 and the carrier layer 1 are separated, the present embodiment further limits the peeling force between the functional layer 3 and the carrier layer 1 to less than or equal to 0.8 N / cm after N pressing times. For example, after N pressing times, the peeling force between the functional layer 3 and the carrier layer 1 can be 0.8 N / cm, 0.75 N / cm, 0.7 N / cm, 0.65 N / cm, 0.6 N / cm, 0.55 N / cm, 0.5 N / cm, 0.45 N / cm, etc. This embodiment does not make specific limitations here, so as to ensure that after multiple pressings, the peeling force between the functional layer 3 and the carrier layer 1 will not be too large. When separating the boards, the carrier layer 1 will not be difficult to peel off from the functional layer 3 due to excessive peeling force, which effectively ensures the peeling stability of the metal foil and further ensures the production yield of the ETS process and the coreless process.

[0051] In this embodiment, the number of pressing times N is a positive integer greater than or equal to 5. For example, N can be 5, 6, 7, 8, 9, 10, etc., which is not specifically limited in this embodiment.

[0052] As a preferred solution, the peeling layer 2 is made of an organic material, an inorganic material or a mixed material; wherein the mixed material includes the organic material and the inorganic material.

[0053] Specifically, the material of the peeling layer 2 in this embodiment can be an organic material, such as nitrogen-containing compounds, sulfur-containing compounds and carboxylic acids, among which nitrogen-containing organic compounds include the following types: ketoxime compounds, transition metal chelates, organic amine compounds and nitrogen heterocyclic compounds; ketoxime compounds include phenyl oxime, o-nitrobenzene oxime, etc.; transition metal chelates include nitrosopropanedione, etc.; organic amine compounds include aniline, diethylamine, etc.; nitrogen heterocyclic compounds include pyridine, imidazole, etc.; of course, in addition to the nitrogen-containing organic compounds mentioned above, other nitrogen-containing organic compounds can also be used, and this embodiment will not be described in detail here. Types of sulfur-containing organic compounds include disulfide compounds and thiosulfide compounds; disulfide compounds include ethylene disulfide, propylene disulfide, etc.; thiosulfide compounds include thiophenyl ether, thioethyl ether, etc.; of course, in addition to the sulfur-containing organic compounds mentioned above, other sulfur-containing organic compounds can also be used, and this embodiment will not be described in detail here.

[0054] In addition, the material of the peeling layer 2 in this embodiment can also be an inorganic material, including a metal base layer or alloy layer, such as an alloy made of any one or more materials of copper, nickel, silicon, molybdenum, titanium and niobium, which is not specifically limited in this embodiment.

[0055] In addition, the material of the peeling layer 2 in the present embodiment can also be a mixed material including an organic material and an inorganic material, wherein the organic material can adopt the nitrogen-containing compound, the sulfur-containing compound, and the carboxylic acid mentioned above, and the inorganic material can adopt an alloy made of any one or more of the materials mentioned above, such as copper, nickel, silicon, molybdenum, titanium, and niobium, and the present embodiment is not limited here.

[0056] In the present embodiment, the peeling layer 2 is processed on the carrier layer 1 by any one of an electroplating process, a vacuum sputtering process, and a coating process.

[0057] As a preferred solution, an anti-oxidation layer 7 is further included, which is arranged on the functional layer 3 away from the side surface of the peeling layer 2.

[0058] Specifically, please refer to Figure 6 In order to strengthen the anti-oxidation effect of the metal foil before application, the present embodiment is provided with an anti-oxidation layer 7 on the functional layer 3 away from the side surface of the peeling layer 2, so that the side surface of the functional layer 3 away from the peeling layer 2 is not easily polluted by moisture, dust, and other objects in the air, and can maintain a relatively dry and clean surface state, and is not easily oxidized, which can ensure the normal storage and use of the metal foil, and is conducive to prolonging the storage time.

[0059] As one of the optional embodiments, the anti-oxidation layer 7 includes a non-metallic layer and / or an inorganic metal layer, wherein the non-metallic layer includes an organic layer, and the material of the organic layer adopts a high-molecular organic material such as polyimide and PET. Taking polyimide as an example, polyimide has excellent high-temperature stability and chemical stability, and has good adhesion with the functional layer 3 (such as copper foil). By coating a polyimide solution or suspension on the surface of the functional layer 3 (such as copper foil) and performing heat treatment, a uniform anti-oxidation layer 7 can be formed. Such an anti-oxidation layer 7 can effectively protect the functional layer 3 (such as copper foil) from oxidation and has good adhesion, and is suitable for use in the fields of electronics, communications, and aerospace. Polyimide as the material of the anti-oxidation layer 7 has excellent high-temperature resistance. Polyimide material can still maintain stable chemical and physical properties at high temperatures, and can withstand temperatures above 400 degrees Celsius. Therefore, using polyimide as the material of the anti-oxidation layer 7 not only protects the functional layer 3 (such as copper foil) from oxidation, but also maintains stable performance in high-temperature environments, and is suitable for applications in high-temperature environments.

[0060] In addition, the material of the organic layer can also be any one of nitrogen-containing organic compounds, sulfur-containing organic compounds and hydroxy acids. Nitrogen-containing organic compounds include the following types: ketoxime compounds, transition metal chelators, organic amine compounds and nitrogen heterocyclic compounds; ketoxime compounds, such as phenyloxime and o-nitrophenyloxime, can form complexes with the surface of metal oxides, thereby slowing down the oxidation rate of the metal; transition metal chelators, such as nitrosopropanedione, can form stable coordination complexes with metals, effectively preventing the oxidation reaction of the metal; organic amine compounds, such as aniline and diethylamine, can react with the surface of metal oxides to form amine copper complexes, thereby playing an antioxidant role; nitrogen heterocyclic compounds, such as pyridine and imidazole, have strong coordination ability and can form stable complexes with metals, thereby slowing down the oxidation rate of the metal. Of course, in addition to the nitrogen-containing organic compounds mentioned above, other nitrogen-containing organic compounds with antioxidant ability in the prior art can also be used, and this embodiment will not be described in detail here. Sulfur-containing organic compounds, such as mercaptoethanol and mercaptopropanol, can react with the surface of metal oxides to form relatively stable complexes, thereby slowing down the oxidation rate of the metal. Types of sulfur-containing organic compounds include disulfide compounds and thiosulfide compounds; disulfide compounds, such as ethylene disulfide and propylene disulfide, can form complexes with metal surfaces and have certain antioxidant properties; thiosulfide compounds, such as thiophenyl ether and thioethyl ether, can react chemically with metals to slow down the oxidation process of metals. Of course, in addition to the sulfur-containing organic compounds mentioned above, other sulfur-containing organic compounds with antioxidant properties in the prior art can also be used, and this embodiment will not be described in detail here. Hydroxylic acids can form stable complexes with metal ions by chelating metal ions, thereby slowing down the oxidation rate of metals and having certain antioxidant properties.

[0061] Furthermore, the material of the inorganic metal layer includes at least one of nickel, copper, chromium, zinc and the like and / or an alloy including at least one of them, which is not specifically limited in this embodiment.

[0062] A second aspect of the embodiments of the present invention provides a metal-clad laminate, wherein the metal-clad laminate is made of the functional layer in the metal foil described in any embodiment of the first aspect as one of the materials.

[0063] The metal foil and metal-clad laminate provided by the embodiments of the present invention have the following beneficial effects:

[0064] (1) By limiting the average water drop angle of the first peeling surface on the carrier layer that contacts the peeling layer and / or the second peeling surface on the functional layer that contacts the peeling layer to be greater than or equal to 100°, it is possible to ensure that the peeling point between the carrier layer and the functional layer is a hydrophobic interface, thereby effectively preventing the infiltration of chemicals during wet processes such as electroplating and etching in the ETS\coreless process, and there is no need for additional edge sealing or improving the bonding strength between the carrier layer and the functional layer. It is ensured that after multiple pressings, the functional layer and the carrier layer can be smoothly peeled off when the board is separated, effectively improving the production yield, while avoiding the increase in production costs due to the increase in production processes.

[0065] (2) By limiting the difference between the maximum water drop angle and the minimum water drop angle among the water drop angles of M test points selected arbitrarily on the first peeling surface and / or the second peeling surface to be less than or equal to 5°, the hydrophobicity of the entire peeling surface can be ensured to be more uniform, thereby ensuring that in the wet processes such as electroplating and etching in the ETS\coreless process, the peeling point between the carrier layer and the functional layer can effectively avoid the penetration of chemical solutions in all directions.

[0066] (3) By limiting the peeling force between the functional layer and the carrier layer to 0.05 N / cm to 0.6 N / cm, the carrier layer will not be difficult to peel off from the functional layer due to excessive peeling force, nor will the functional layer easily fall off from the carrier layer due to excessive peeling force. This can effectively ensure the peeling stability of the metal foil and further ensure the production yield of the ETS process and the coreless process.

[0067] (4) By limiting the peeling force between the functional layer and the carrier layer to less than or equal to 0.8 N / cm after N times of lamination, it can be ensured that the peeling force between the functional layer and the carrier layer will not be too large after multiple laminations. When separating the panels, the carrier layer will not be difficult to peel off from the functional layer due to excessive peeling force, which effectively ensures the peeling stability of the metal foil and further ensures the production yield of the ETS process and the coreless process.

[0068] In order to fully demonstrate the beneficial effects of the metal foil and metal-clad laminate provided by the embodiments of the present invention, several embodiments and comparative examples are described below.

[0069] Example 1

[0070] A metal foil comprises a carrier layer, a peeling layer and a functional layer stacked in sequence, wherein the surface of the carrier layer close to the peeling layer is a first peeling surface, and the surface of the functional layer close to the peeling layer is a second peeling surface; the average water drop angle of the first peeling surface is 114°, and the average water drop angle of the second peeling surface is 126°.

[0071] Example 2

[0072] A metal foil comprises a carrier layer, a release layer, a functional layer and an oxidation-resistant layer which are sequentially stacked, a side surface of the carrier layer close to the release layer is a first release surface, and a side surface of the functional layer close to the release layer is a second release surface; the average water drop angle of the first release surface is 125°, and the average water drop angle of the second release surface is 132°.

[0073] The difference between the maximum water drop angle and the minimum water drop angle of the water drop angles of 14 test points randomly selected in the first release surface is 3.2°, and the difference between the maximum water drop angle and the minimum water drop angle of the water drop angles of 14 test points randomly selected in the second release surface is 2°.

[0074] Example 3

[0075] A metal foil comprises a carrier layer, a release layer, a functional layer and an oxidation-resistant layer which are sequentially stacked, a side surface of the carrier layer close to the release layer is a first release surface, and a side surface of the functional layer close to the release layer is a second release surface; the average water drop angle of the first release surface is 140°, and the average water drop angle of the second release surface is 100°.

[0076] The difference between the maximum water drop angle and the minimum water drop angle of the water drop angles of 20 test points randomly selected in the first release surface is 5°, and the difference between the maximum water drop angle and the minimum water drop angle of the water drop angles of 15 test points randomly selected in the second release surface is 2.8°.

[0077] The release force between the functional layer and the carrier layer is 0.15 N / cm, and after 8 times of pressing, the release force between the functional layer and the carrier layer is 0.6 N / cm.

[0078] Example 4

[0079] A metal foil comprises a carrier layer, a release layer, a functional layer and an oxidation-resistant layer which are sequentially stacked, a side surface of the carrier layer close to the release layer is a first release surface, and a side surface of the functional layer close to the release layer is a second release surface; the average water drop angle of the first release surface is 137°, and the average water drop angle of the second release surface is 145°.

[0080] The difference between the maximum water drop angle and the minimum water drop angle of the water drop angles of 10 test points randomly selected in the first release surface is 1°, and the difference between the maximum water drop angle and the minimum water drop angle of the water drop angles of 18 test points randomly selected in the second release surface is 4.2°.

[0081] The release force between the functional layer and the carrier layer is 0.35 N / cm, and after 6 times of pressing, the release force between the functional layer and the carrier layer is 0.65 N / cm.

[0082] Comparative Example 1

[0083] A metal foil comprises a carrier layer, a peeling layer and a functional layer stacked in sequence, wherein the surface of the carrier layer close to the peeling layer is a first peeling surface, and the surface of the functional layer close to the peeling layer is a second peeling surface; the average water drop angle of the first peeling surface is 34°, and the average water drop angle of the second peeling surface is 48°.

[0084] Comparative Example 2

[0085] A metal foil comprising a carrier layer, a release layer, and a functional layer stacked in sequence. The surface of the carrier layer near the release layer is a first release surface, and the surface of the functional layer near the release layer is a second release surface. The first release surface has an average water drop angle of 60°, while the second release surface has an average water drop angle of 45°. The bonding strength between the functional layer and the carrier layer is 2 N / cm.

[0086] The ETS process was used to fabricate ultrafine circuits on the metal foils in the above-mentioned embodiments and comparative examples, and observations were made as to whether there was any chemical infiltration or difficulty in separating the carrier layer during the ETS process. The results are shown in Table 1 below:

[0087] Table 1 ETS process preparation results of various metal foils

[0088] Detection object Preparation result of ETS process Example 1 The drug solution did not penetrate between the functional layer and the carrier layer, and the plate could be separated smoothly Example 2 The drug solution did not penetrate between the functional layer and the carrier layer, and the plate could be separated smoothly Example 3 The drug solution did not penetrate between the functional layer and the carrier layer, and the plate could be separated smoothly Example 4 The drug solution did not penetrate between the functional layer and the carrier layer, and the plate could be separated smoothly Comparative Example 1 The drug solution penetrated between the functional layer and the carrier layer, and delamination occurred Comparative Example 2 The drug solution did not penetrate between the functional layer and the carrier layer, but the surface of the functional layer was damaged when the plate was separated

[0089] It can be seen that the metal foils in Examples 1 to 4, since the average water drop angles of the first and second peeling surfaces are greater than or equal to 100°, can ensure that the peeling point between the carrier layer and the functional layer is a hydrophobic interface. In the wet processes such as electroplating and etching in the ETS process, it can effectively prevent the penetration of chemicals, and there is no need for additional edge sealing or improving the bonding strength between the carrier layer and the functional layer, ensuring that after multiple pressings, the functional layer and the carrier layer can be smoothly peeled off when the panels are separated.

[0090] In Comparative Example 1, the average water drop angles of the first and second peeling surfaces of the metal foil are both less than 100°, so that the peeling point between the carrier layer and the functional layer is a hydrophilic interface. During the wet processes such as electroplating and etching in the ETS process, chemical infiltration occurs, resulting in delamination and shedding, resulting in the final product being a defective product.

[0091] The metal foil in Comparative Example 2 additionally increases the bonding strength between the functional layer and the carrier layer to 2 N / cm. Although no chemical infiltration occurs during wet processes such as electroplating and etching in the ETS process, the functional layer and the carrier layer are difficult to separate during the depaneling process, and the peeling stability is poor, which ultimately leads to surface damage of the functional layer, making the final product also defective.

[0092] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. 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 It comprises a carrier layer, a peeling layer and a functional layer stacked in sequence, wherein the surface of the carrier layer close to the peeling layer is a first peeling surface, and the surface of the functional layer close to the peeling layer is a second peeling surface; the average water drop angle of the first peeling surface and / or the second peeling surface is greater than or equal to 100°.

2. The metal foil according to claim 1, wherein The water drop angle mean is the average value of the water drop angles of M test points randomly selected from the first peeling surface and / or the second peeling surface; wherein M is a positive integer greater than or equal to 10.

3. The metal foil according to claim 2, wherein The difference between the maximum water drop angle and the minimum water drop angle among the water drop angles of the M test points is less than or equal to 5°.

4. The metal foil according to claim 1, wherein The first peeling surface and / or the second peeling surface has a hydrophobic material layer formed by sputtering or electroplating; Alternatively, two opposite surfaces of the release layer are provided with a hydrophobic material layer formed by sputtering or electroplating.

5. The metal foil according to claim 4, wherein The hydrophobic material layer includes silicon dioxide and fluorosilane.

6. The metal foil according to claim 1, wherein The peeling force between the functional layer and the carrier layer is 0.05 N / cm to 0.6 N / cm.

7. The metal foil according to claim 1, wherein After N times of lamination, the peeling force between the functional layer and the carrier layer is less than or equal to 0.8 N / cm; wherein N is a positive integer greater than or equal to 5.

8. The metal foil according to claim 1, wherein The peeling layer is made of an organic material, an inorganic material or a mixed material; wherein the mixed material includes the organic material and the inorganic material.

9. The metal foil according to claim 1, wherein The invention also includes an anti-oxidation layer, which is arranged on a surface of the functional layer on a side away from the peeling layer.

10. A metal-clad laminate, characterized in that: The metal-clad laminate is produced by using the functional layer in the metal foil according to any one of claims 1 to 9 as one of its materials.

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