Composite layer carrier copper foil and preparation method thereof, method for realizing carrier-attached ultra-thin copper foil easy to peel from composite layer, ultra-thin copper foil and preparation method of ultra-thin copper foil

Abstract

The invention relates to the technical field of copper foils, in particular to a composite layer carrier copper foil, a preparation method of the composite layer carrier copper foil, a method for easily stripping an ultrathin copper foil with a carrier from a composite layer, the ultrathin copper foil and a preparation method of the ultrathin copper foil. The composite layer comprises a nickel layer and an organic layer of a tetrazole compound from inside to outside, and the tetrazole compound has a structure as shown in the following formula (1): R1 is selected from hydrogen, amino, a tetrazole group or a group containing 1-5 carbon atoms; r1 is selected from hydrogen, sulfydryl, amino or a group containing 1-5 carbon atoms, R2 is selected from hydrogen, sulfydryl, amino or a group containing 1-5 carbon atoms, and the groups containing 1-5 carbon atoms in R1 and R2 are respectively selected from C1-C5 alkyl groups, carboxyl-substituted C1-C5 alkyl groups and sulfenyl-substituted C1-C5 alkyl groups. The composite layer carrier copper foil provided by the invention has the characteristics of easy stripping and stable stripping performance.

Description

Technical Field

[0001] The present invention relates to the technical field of copper foil, and in particular to a composite layer carrier copper foil and a preparation method thereof, a method for realizing easy-to-peel composite layer ultra-thin copper foil with a carrier, and an ultra-thin copper foil and a preparation method thereof. Background Art

[0002] Ultra-thin copper foil (1-5μm) has become a core material for high-density interconnect (HDI) circuit manufacturing and lithium-ion battery anode current collectors due to its excellent conductivity and ductility. In the field of integrated circuit packaging substrates, this material must meet the requirements of precision processing below 5μm. However, ultra-thin copper foil produced by traditional processes suffers from mechanical strength degradation and is prone to defects such as wrinkling and fracture, seriously affecting the process qualification rate and service reliability of end products.

[0003] In response to the above-mentioned technical bottlenecks, the industry has proposed a solution for preparing copper foil with a carrier. CN111787714A discloses a method for preparing an easy-to-peel off ultra-thin copper foil with a carrier by designing a composite structure of a base carrier layer and adopting an electroplating process. However, the proposed method of constructing an intermediate layer and a peeling layer by magnetron sputtering to obtain an ultra-thin copper foil has high equipment costs and is difficult to apply to industrial production. This technical architecture includes a sandwich structure of a carrier layer, a peeling layer and a functional copper layer, wherein the peeling layer is a key layer for interface regulation and must simultaneously meet the following requirements: a) ensuring the interface stability between the carrier and the copper foil during the pressing process; b) achieving controllable peeling in the subsequent process. When the peel strength is lower than the critical value, the foil is prone to displacement and shedding during the processing; exceeding the threshold value will lead to interface locking, resulting in copper foil tearing defects. Regarding the appropriate peel strength between the carrier foil and the ultra-thin copper foil, generally speaking, the peel strength needs to be controlled within 5-300gf / cm, and 50-300gf / cm is a good range.

[0004] Current peel layer technologies are primarily categorized into three systems: organic, metallic, and composite. Organic peel layers, typically composed of organic compounds containing nitrogen and sulfur or carboxylic acids, offer advantages such as minimal environmental impact and simplified production processes, but are prone to issues such as low peel strength and poor electrical conductivity. Metal peel layers generally consist of a single metal or alloy. While this can overcome the disadvantages of poor electrical conductivity, they are susceptible to diffusion and localized mechanical locking during high-temperature lamination, making peeling difficult. Compared to single inorganic or organic peel layers, composite peel layers are receiving more attention.

[0005] Rare earth ions (Ln 3+) Based on its trivalent state characteristics (high charge density, unoccupied 4f orbitals, and high coordination tendency), it can synergize through electrostatic attraction and coordination bonds to form a highly stable coordination system with organic molecules containing coordinating atoms such as O, N, S, and P. This property shows potential application value in the fields of functionalized copper foil surface modification and controlled peeling.

[0006] However, there are few reports on carrier copper foil in the domestic market regarding how to achieve stable separation of ultra-thin copper foil from carrier foil. Overall, the industry has yet to achieve breakthroughs in the pursuit of stable, convenient, and controllable peel layer preparation technology, and still faces many technical bottlenecks that need to be overcome. Summary of the Invention

[0007] The purpose of the present invention is to overcome the problem in the prior art that ultra-thin copper foil and carrier foil are difficult to separate stably, and to provide a composite layer carrier copper foil and a preparation method thereof, a method for realizing easy peeling of ultra-thin copper foil with a carrier on a composite layer, an ultra-thin copper foil and a preparation method thereof. The composite layer carrier copper foil has the characteristics of easy peeling and stable peeling performance; the ultra-thin copper foil with a carrier has a uniform thickness and a pure interface, and can be stably peeled before and after high-temperature pressing; at the same time, the obtained ultra-thin copper foil has fine grains, low roughness and excellent peeling performance.

[0008] According to a first aspect of the present invention, the present invention provides a composite layer carrier copper foil, the carrier copper foil comprising a copper foil and a composite layer formed on a smooth surface of the copper foil, the composite layer comprising, from the inside to the outside, a nickel layer and an organic layer of a tetrazole compound, the tetrazole compound having a structure as shown in the following formula (1):

[0009]

[0010] wherein R1 is selected from hydrogen, amino, tetrazole group or a group containing 1-5 carbon atoms; R2 is selected from hydrogen, thiol, amino or a group containing 1-5 carbon atoms,

[0011] The groups containing 1 to 5 carbon atoms in R1 and R2 are independently selected from C1-C5 alkyl groups, C1-C5 alkyl groups substituted with carboxyl groups, and C1-C5 alkyl groups substituted with thio groups.

[0012] According to a second aspect of the present invention, the present invention provides a method for preparing a composite layer carrier copper foil, the method comprising:

[0013] Electroplating the smooth surface of the copper foil: Electrodepositing in a nickel plating solution to form a nickel layer;

[0014] Then, immersion plating is performed: an organic layer is formed by immersing or coating an aqueous solution containing a tetrazole compound, wherein the tetrazole compound has a structure shown in the following formula (1):

[0015]

[0016] wherein R1 is selected from hydrogen, amino, tetrazole group or a group containing 1-5 carbon atoms; R2 is selected from hydrogen, thiol, amino or a group containing 1-5 carbon atoms,

[0017] The groups containing 1 to 5 carbon atoms in R1 and R2 are independently selected from C1-C5 alkyl groups, C1-C5 alkyl groups substituted with carboxyl groups, and C1-C5 alkyl groups substituted with thio groups.

[0018] According to a third aspect of the present invention, the present invention provides a composite layer carrier copper foil prepared by the method provided by the present invention.

[0019] According to the fourth aspect of the present invention, the present invention provides a method for realizing easy-to-peel ultra-thin copper foil with a carrier by a composite layer, the method comprising: in a copper plating solution, electroplating the composite surface of the composite layer carrier copper foil of the present invention or the composite surface of the composite layer carrier copper foil prepared by the method provided by the present invention to form an ultra-thin copper foil, thereby obtaining an ultra-thin copper foil with a carrier.

[0020] According to a fifth aspect of the present invention, the present invention provides a method for preparing an ultra-thin copper foil, wherein the ultra-thin copper foil with a carrier prepared by the method provided by the present invention is mechanically peeled off to obtain the ultra-thin copper foil.

[0021] According to a sixth aspect of the present invention, the present invention provides an ultra-thin copper foil prepared by the method provided by the present invention.

[0022] The composite layer carrier copper foil provided by the present invention has the characteristics of being easy to peel and having stable peeling performance.

[0023] The preparation method of the composite layer carrier copper foil provided by the present invention can form a thin and uniform composite layer, which can significantly improve the peeling integrity and process stability of the carrier copper foil; and the composite layer can serve as a corrosion inhibition layer to prevent the oxidation of the carrier copper foil, facilitating subsequent recycling; at the same time, the prepared composite layer carrier copper foil has the characteristics of easy peeling and stable peeling performance; the method of the present invention is simple to operate, low in cost, and convenient for industrial application.

[0024] The ultra-thin copper foil with a carrier prepared by the method provided by the present invention has the characteristics of stable peeling performance, uniform thickness, and pure interface; at the same time, the organic matter used in the method is easily soluble in organic solvents and water, and will not have an adverse effect on the production process of the ultra-thin copper foil in printed circuit boards.

[0025] The ultra-thin copper foil prepared by the method provided by the present invention has the characteristics of fine grains, low roughness and excellent peeling performance. At the same time, the method of the present invention is simple to operate, low in cost, and convenient for industrial application. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a scanning electron microscope (SEM) image of the ultra-thin copper foil (deposition surface above the peeling layer) of Example 10 (magnification 10,000 times);

[0027] Figure 2 This is a scanning electron microscope (SEM) image of the ultra-thin copper foil (laminated peeling layer) of Example 10 (magnification 10,000 times);

[0028] Figure 3 This is a scanning electron microscope (SEM)-energy dispersive spectrometry (EDS) image of the ultra-thin copper foil (laminated peeling layer) of Example 10;

[0029] Figure 4 This is a scanning electron microscope (SEM) image of the cross section of the ultra-thin copper foil with a carrier of Example 10 (magnification 10,000 times). DETAILED DESCRIPTION

[0030] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0031] In the present invention, the smooth surface of the copper foil refers to the side where the copper particles grow on the substrate. For the copper foil, it is the side with relatively lower roughness, while for the ultra-thin copper foil prepared in the present invention, it is the side with higher roughness; the matte surface of the copper foil refers to the side where the copper particles are exposed. For the supporting copper foil, it is the side with higher roughness, while for the ultra-thin copper foil prepared in the present invention, it is the side with lower roughness.

[0032] The present invention provides a composite layer carrier copper foil, which includes a copper foil and a composite layer formed on a smooth surface of the copper foil. The composite layer includes, from the inside to the outside, a nickel layer and an organic layer containing a tetrazole compound. The tetrazole compound has a structure shown in the following formula (1):

[0033]

[0034] wherein R1 is selected from hydrogen, amino, tetrazole group or a group containing 1-5 carbon atoms; R2 is selected from hydrogen, thiol, amino or a group containing 1-5 carbon atoms,

[0035] The groups containing 1 to 5 carbon atoms in R1 and R2 are independently selected from C1-C5 alkyl groups, C1-C5 alkyl groups substituted with carboxyl groups, and C1-C5 alkyl groups substituted with thio groups.

[0036] In the present invention, any carrier copper foil having the aforementioned composition and structure can achieve the objectives of the present invention. The composition of the organic layer of the tetrazole compound can be selected from a wide range, as exemplified below, but not intended to limit the scope of the present invention. According to a preferred embodiment of the present invention, the organic layer of the tetrazole compound contains a rare earth metal salt. The composite carrier copper foil prepared using the aforementioned preferred tetrazole compound having an organic layer containing a rare earth metal salt has the characteristics of easy peeling and stable peeling performance, while also allowing the resulting ultra-thin copper foil to have fine grains, low roughness, and excellent peeling performance.

[0037] In the present invention, there is no special requirement for the type and content of the rare earth metal salt. The following is an exemplary description, but it does not limit the scope of the present invention.

[0038] According to a preferred embodiment of the present invention, the mass ratio of the tetrazole compound to the rare earth metal salt is (0.07-50):1, preferably (0.75-14):1.

[0039] According to a preferred embodiment of the present invention, the rare earth metal salt includes one or more of nitrates, chlorates and sulfates, preferably one or more of lanthanum nitrate, cerium nitrate, samarium nitrate and dysprosium nitrate.

[0040] The composite layer carrier copper foil prepared using the aforementioned preferred rare earth metal salt types and contents has the characteristics of easy peeling and stable peeling performance. At the same time, the prepared ultra-thin copper foil has fine grains, low roughness, and excellent peeling performance, and can reduce the cost of the present invention.

[0041] In the present invention, any carrier copper foil having the aforementioned composition and structure can achieve the purpose of the present invention. The types of tetrazole compounds can be selected from a wide range of types, which are exemplified below but do not limit the scope of the present invention.

[0042] According to a preferred embodiment of the present invention, the tetrazole compound is selected from one or more of tetrazole, 5-methylthiotetrazole, 5-methyltetrazole, 5-mercapto-1-methyltetrazole, 1H-tetrazole-5-acetic acid, 5-aminotetrazole, 5-ethylthiotetrazole and 5,5-tetrazole diamine salt.

[0043] According to a preferred embodiment of the present invention, the tetrazole compound is tetrazole and 1H-tetrazole-5-acetic acid, and the mass ratio of tetrazole to 1H-tetrazole-5-acetic acid is 1:(2-4).

[0044] According to a preferred embodiment of the present invention, the tetrazole compound is 5,5-tetrazolyl diamine salt and 5-mercapto-1-methyltetrazole, and the mass ratio of 5,5-tetrazolyl diamine salt to 5-mercapto-1-methyltetrazole is 1:(1-3).

[0045] The composite layer carrier copper foil prepared by using the aforementioned preferred tetrazole compound has the characteristics of easy peeling and stable peeling performance, and at the same time, the prepared ultra-thin copper foil has the characteristics of fine grains, low roughness and excellent peeling performance.

[0046] In the present invention, the carrier copper foil having the aforementioned composition and structure can achieve the purpose of the present invention. There are no special requirements for the formation method of the nickel layer. The following is an exemplary description, but it does not limit the scope of the present invention. According to a preferred embodiment of the present invention, the nickel layer is formed by electroplating.

[0047] In the present invention, any carrier copper foil having the aforementioned composition and structure can achieve the purpose of the present invention. There are no special requirements for the method of forming the organic layer. The following is an exemplary description, but does not limit the scope of the present invention. According to a preferred embodiment of the present invention, the organic layer is formed by immersing or coating an aqueous solution containing a tetrazole compound.

[0048] The composite layer carrier copper foil having the above characteristics can achieve the purpose of the present invention. There is no special requirement for its preparation method. The following exemplary description is provided, but the scope of the present invention is not limited thereby. According to a preferred embodiment of the present invention, the present invention provides a preparation method of a composite layer carrier copper foil, which comprises: electroplating the smooth surface of the copper foil: performing electrodeposition in a nickel plating solution to form a nickel layer; and then immersing: immersing or coating with an aqueous solution containing a tetrazole compound to form an organic layer, wherein the tetrazole compound has a structure shown in the following formula (1):

[0049]

[0050] wherein R1 is selected from hydrogen, amino, tetrazole group or a group containing 1-5 carbon atoms; R2 is selected from hydrogen, thiol, amino or a group containing 1-5 carbon atoms,

[0051] The groups containing 1 to 5 carbon atoms in R1 and R2 are independently selected from C1-C5 alkyl groups, C1-C5 alkyl groups substituted with carboxyl groups, and C1-C5 alkyl groups substituted with thio groups.

[0052] The preparation method of the composite layer carrier copper foil of the present invention can form a thin and uniform composite layer, which can significantly improve the peeling integrity and process stability of the carrier copper foil; and the composite layer can serve as a corrosion inhibition layer to prevent the oxidation of the carrier copper foil, facilitating subsequent recycling; at the same time, the prepared composite layer carrier copper foil has the characteristics of easy peeling and stable peeling performance; the method of the present invention is simple to operate, low in cost, and convenient for industrial application.

[0053] In the present invention, according to the needs, a copper foil with a thickness of 18-35 μm is selected for use in preparing the composite layer carrier copper foil of the present invention.

[0054] In the present invention, solutions of different concentrations are prepared as needed. If the solvent type is not specifically specified, water is used as the solvent by default, and solutions of different concentrations can be prepared by adjusting the amount of water added. This is well known to those skilled in the art, and the specific operation will not be repeated here.

[0055] In the present invention, the copper foil needs to be degreased and pickled before electroplating or immersion plating.

[0056] Degreasing is a routine operation in this field, and it only needs to remove impurities on the surface of the copper foil. There are no special requirements for the specific operation steps. For example, the copper foil can be immersed in a degreasing liquid.

[0057] In the present invention, in the degreasing step, there are no special requirements for the composition of the degreasing liquid. The following is an exemplary description, but does not limit the scope of the present invention. According to a preferred embodiment of the present invention, the composition of the degreasing liquid includes 2-5wt% NaOH, 4-10wt% Na2CO3, 5-20wt% Na2PO4·12H2O, and the balance is water.

[0058] In the present invention, there is no special requirement for the oil removal conditions. The following is an exemplary description, but it does not limit the scope of the present invention.

[0059] According to a preferred embodiment of the present invention, the oil removal temperature is 30-60°C.

[0060] According to a preferred embodiment of the present invention, the oil removal time is 30-90 seconds.

[0061] In the present invention, pickling is a conventional operation in the art, as long as the oxides on the surface of the copper foil can be removed; there are no special requirements for the specific operation steps, for example, the degreased copper foil can be immersed in a pickling solution.

[0062] In the present invention, in the pickling step, there are no special requirements for the composition of the pickling solution. The following is an exemplary description, but does not limit the scope of the present invention. According to a preferred embodiment of the present invention, the composition of the pickling solution includes 5-20wt% nitric acid, 5-20wt% phosphoric acid, and the balance is water.

[0063] In the present invention, there is no special requirement for the pickling conditions. The following is an exemplary description, but it does not limit the scope of the present invention.

[0064] According to a preferred embodiment of the present invention, the pickling temperature is 10-40°C.

[0065] According to a preferred embodiment of the present invention, the pickling time is 10-40s.

[0066] In the present invention, before the electroplating operation, the rough surface of the copper foil is attached to the cathode titanium plate with insulating adhesive as needed.

[0067] In the present invention, after the nickel layer is formed by electroplating, the organic layer is formed by immersion plating, and the ultra-thin copper foil is formed by electrodeposition, deionized water is required for cleaning and drying. There is no special requirement for the drying conditions, as long as the deionized water on the surface is removed.

[0068] In the present invention, during immersion plating, as long as the aqueous solution contains a tetrazole compound, the purpose of the present invention can be achieved. There are no special requirements for the other components and contents of the aqueous solution. The following is an exemplary description, but it does not limit the scope of the present invention.

[0069] According to a preferred embodiment of the present invention, the aqueous solution containing tetrazole compounds contains rare earth metal salts.

[0070] According to a preferred embodiment of the present invention, the content of the rare earth metal salt is 0.2-7 g / L, preferably 0.5-4 g / L.

[0071] The composite layer carrier copper foil prepared by using the above-mentioned preferred rare earth metal salt composition and content has the characteristics of easy peeling and stable peeling performance. At the same time, the prepared ultra-thin copper foil has the characteristics of fine grains, low roughness and excellent peeling performance.

[0072] In the present invention, a wide range of rare earth metal salts can be selected. The following exemplary description is provided, but does not limit the scope of the present invention. According to a preferred embodiment of the present invention, the rare earth metal salt comprises one or more of nitrates, chlorates, and sulfates, preferably one or more of lanthanum nitrate, cerium nitrate, samarium nitrate, and dysprosium nitrate. The composite layer carrier copper foil prepared using the aforementioned preferred rare earth metal salts exhibits easy peeling and stable peeling performance. Furthermore, the resulting ultra-thin copper foil exhibits fine grains, low roughness, and excellent peeling performance, while also reducing the cost of the present invention.

[0073] In the present invention, when the aqueous solution containing the tetrazole compound contains a rare earth metal salt, the pH needs to be adjusted to 4-5 before the organic layer is plated. There is no special requirement for the pH adjuster. For example, acetic acid is used to adjust the pH of the plating solution.

[0074] In the present invention, the tetrazole compound content in the aqueous solution containing the tetrazole compound can be selected within a wide range. The following exemplary description is provided, but does not limit the scope of the present invention. According to a preferred embodiment of the present invention, the tetrazole compound content is 0.5-10 g / L, preferably 3-7 g / L. Using the aforementioned preferred tetrazole compound content allows for uniform distribution of the organic layer of the composite carrier copper foil, while also providing the advantage of stable peel strength for the resulting ultra-thin copper foil.

[0075] In the present invention, the types of tetrazole compounds can be selected from a wide range. The following exemplary description is provided, but the scope of the present invention is not limited thereto. According to a preferred embodiment of the present invention, the tetrazole compound is selected from one or more of tetrazole, 5-methylthiotetrazole, 5-methyltetrazole, 5-mercapto-1-methyltetrazole, 1H-tetrazole-5-acetic acid, 5-aminotetrazole, 5-ethylthiotetrazole and 5,5-bi-tetrazole diamine salt.

[0076] According to a preferred embodiment of the present invention, the tetrazole compound is tetrazole and 1H-tetrazole-5-acetic acid, and the mass ratio of tetrazole to 1H-tetrazole-5-acetic acid is 1:(2-4).

[0077] According to a preferred embodiment of the present invention, the tetrazole compound is 5,5-tetrazolyl diamine salt and 5-mercapto-1-methyltetrazole, and the mass ratio of 5,5-tetrazolyl diamine salt to 5-mercapto-1-methyltetrazole is 1:(1-3).

[0078] The composite layer carrier copper foil prepared by using the aforementioned preferred tetrazole compound has the characteristics of easy peeling and stable peeling performance, and at the same time, the prepared ultra-thin copper foil has the characteristics of fine grains, low roughness and excellent peeling performance.

[0079] In the present invention, there is no special requirement for the immersion plating conditions. The following is an exemplary description, but it does not limit the scope of the present invention.

[0080] According to a preferred embodiment of the present invention, the immersion plating temperature is 15-25°C.

[0081] According to a preferred embodiment of the present invention, the immersion plating time is 5-60s.

[0082] In the present invention, after the copper foil plated with the nickel layer is immersed in or coated with an aqueous solution containing a tetrazole compound, it is necessary to dry it to form an organic layer.

[0083] In the present invention, there is no special requirement for the drying conditions. The following is an exemplary description, but it does not limit the scope of the present invention.

[0084] According to a preferred embodiment of the present invention, the drying is carried out in a drying box or a drying oven.

[0085] According to a preferred embodiment of the present invention, the temperature is 150-200°C, preferably 180-190°C.

[0086] According to a preferred embodiment of the present invention, the time is 1-10 s, preferably 3-5 s.

[0087] In the present invention, during electroplating, the composition of the nickel plating solution can be selected in a wide range. The following is an exemplary description, but does not limit the scope of the present invention. According to a preferred embodiment of the present invention, the nickel plating solution contains a nickel source, a pH buffer, a sulfate, a chloride salt and a nickel plating additive.

[0088] In the present invention, there are no special requirements for the origin, type and concentration of the nickel source. The following is an exemplary description, but it does not limit the scope of the present invention.

[0089] According to a preferred embodiment of the present invention, the nickel source is a soluble nickel salt, preferably one or more of nickel sulfate, nickel chloride, nickel sulfamate, nickel carbonate, nickel nitrate, and nickel acetate; more preferably nickel sulfate.

[0090] According to a preferred embodiment of the present invention, the concentration of the nickel source is 150-275 g / L.

[0091] In the present invention, there is no particular requirement for the type and concentration of the pH buffer. The following is an exemplary description, but does not limit the scope of the present invention.

[0092] According to a preferred embodiment of the present invention, the pH buffer comprises one or more of boric acid, citric acid, sodium citrate, sodium acetate, acetic acid, NH2SO3H, sodium dihydrogen phosphate, phosphoric acid, and sodium fluoroborate, preferably boric acid.

[0093] According to a preferred embodiment of the present invention, the concentration of the pH buffer is 20-60 g / L.

[0094] In the present invention, there is no special requirement for the type and concentration of sulfate. The following is an exemplary description, but it does not limit the scope of the present invention.

[0095] According to a preferred embodiment of the present invention, the sulfate includes one or more of sodium sulfate, magnesium sulfate, and ammonium sulfate, preferably sodium sulfate.

[0096] According to a preferred embodiment of the present invention, the concentration of the sulfate is 20-40 g / L.

[0097] In the present invention, there is no special requirement for the type and concentration of the chloride salt. The following is an exemplary description, but it does not limit the scope of the present invention.

[0098] According to a preferred embodiment of the present invention, the chloride salt includes one or more of sodium chloride and potassium chloride, preferably sodium chloride.

[0099] According to a preferred embodiment of the present invention, the concentration of the chloride salt is 15-30 g / L.

[0100] In the present invention, there is no special requirement for the type and concentration of the nickel plating additive. The following is an exemplary description, but it does not limit the scope of the present invention.

[0101] According to a preferred embodiment of the present invention, the nickel plating additive includes one or more of thiourea, ethylenethiourea, SDS, sodium saccharin, butynediol, coumarin, 1,5-naphthalene disulfonic acid, and pinene.

[0102] According to a preferred embodiment of the present invention, the concentration of the nickel plating additive is 0.1-4 g / L.

[0103] According to a preferred embodiment of the present invention, the nickel plating additives are thiourea, SDS and sodium saccharin, and the mass ratio of thiourea, SDS and sodium saccharin is 1: (1-3): (1-7.5).

[0104] According to a preferred embodiment of the present invention, the nickel plating additive is ethylene thiourea, SDS and sodium saccharin, and the mass ratio of ethylene thiourea, SDS and sodium saccharin is 1: (2.5-4): (2.5-6).

[0105] In the present invention, there are no special requirements for the electroplating conditions. The following is an exemplary description, but it does not limit the scope of the present invention.

[0106] According to a preferred embodiment of the present invention, the current density is 5-35A / dm 2 .

[0107] According to a preferred embodiment of the present invention, the pH range of electroplating is 3-8.

[0108] According to a preferred embodiment of the present invention, the electroplating temperature is 25-65°C.

[0109] According to a preferred embodiment of the present invention, the electroplating time is 5-45s.

[0110] In the present invention, there is no special requirement for the pH adjuster, and it can be selected and determined according to different nickel plating solutions. For example, ammonia water, as a common pH adjuster, can be applied to the present invention.

[0111] In the present invention, there are no special requirements for the electroplating operation. This is a well-known technology in the art and will not be described in detail here. For example, in the present invention, the polished surface of the copper foil treated with degreasing and pickling is used as the cathode and the iridium-plated titanium plate is used as the anode, and electroplating is performed in a nickel plating solution.

[0112] The present invention provides a composite layer carrier copper foil prepared by the method of the present invention. The composite layer carrier copper foil of the present invention has the characteristics of easy peeling and stable peeling performance. At the same time, the method of the present invention is simple to operate, low in cost, and convenient for industrial application.

[0113] The present invention provides a method for realizing easy-to-peel ultra-thin copper foil with a carrier by composite layer, the method comprising: in a copper plating solution, electroplating the composite surface of the composite layer carrier copper foil provided by the present invention or the composite surface of the composite layer carrier copper foil prepared by the method provided by the present invention to form an ultra-thin copper foil, thereby obtaining the ultra-thin copper foil with a carrier.

[0114] The ultra-thin copper foil with a carrier prepared by the method of the present invention has the characteristics of stable peeling performance, uniform thickness and pure interface; at the same time, the organic matter used in the method is easily soluble in organic solvents and water, and will not have an adverse effect on the production process of the ultra-thin copper foil in printed circuit boards.

[0115] In the present invention, the composition of the copper plating solution can be selected in a wide range. The following exemplary description is provided, but the scope of the present invention is not limited thereto. According to a preferred embodiment of the present invention, the copper plating solution contains a copper source, sulfuric acid, a chloride ion source and a copper plating additive.

[0116] In the present invention, there is no special requirement for the concentrations of the copper source, sulfuric acid, chloride ion source and copper plating additives. The following is an exemplary description, but does not limit the scope of the present invention.

[0117] According to a preferred embodiment of the present invention, the concentration of the copper source is 20-200 g / L.

[0118] According to a preferred embodiment of the present invention, the concentration of sulfuric acid is 20-125 g / L.

[0119] According to a preferred embodiment of the present invention, the concentration of the chloride ion source is 15-50 mg / L.

[0120] According to a preferred embodiment of the present invention, the concentration of the copper plating additive is 2-70 mg / L.

[0121] In the present invention, the types of copper plating additives can be selected from a wide range. The following is an exemplary description, but it does not limit the scope of the present invention. According to a preferred embodiment of the present invention, the copper plating additive includes one or more of SPS, collagen, PEG, sodium thiopropane sulfonate, HEC, allyl polyoxyethylene ether, and sodium phenyl disulfide propane sulfonate.

[0122] According to a preferred embodiment of the present invention, the copper plating additives are SPS, collagen, PEG and sodium thiopropane sulfonate, and the mass ratio of SPS, collagen, PEG and sodium thiopropane sulfonate is (3-4): (3-5): (3-4): 1.

[0123] In the present invention, there is no special requirement for the origin and type of the copper source. The following is an exemplary description, but does not limit the scope of the present invention. According to a preferred embodiment of the present invention, the copper source is a soluble copper salt, preferably copper sulfate.

[0124] In the present invention, there is no special requirement for the origin and type of the chloride ion source. The following is an exemplary description, but does not limit the scope of the present invention. According to a preferred embodiment of the present invention, the chloride ion source includes one or more of HCl and NaCl.

[0125] In the present invention, there is no special requirement for the electrodeposition conditions. The following is an exemplary description, but it does not limit the scope of the present invention.

[0126] According to a preferred embodiment of the present invention, the current density is 5-35A / dm 2 .

[0127] According to a preferred embodiment of the present invention, the electroplating temperature is 25-55°C.

[0128] According to a preferred embodiment of the present invention, the deposition time is 40-200 s.

[0129] In the present invention, there are no special requirements for the electrodeposition operation. This is a well-known technology in the art and will not be described in detail here. For example, in the present invention, the composite surface of the composite layer carrier copper foil is used as the cathode and the iridium-plated titanium plate is used as the anode to perform electrodeposition in a copper plating solution.

[0130] The present invention provides a method for preparing an ultra-thin copper foil. The method comprises mechanically peeling the ultra-thin copper foil with a carrier prepared by the method of the present invention to obtain the ultra-thin copper foil. The ultra-thin copper foil prepared by the method of the present invention has fine grains, low roughness, and excellent peelability. The method of the present invention is simple to operate, low in cost, and suitable for industrial application.

[0131] In the present invention, the mechanical method is a conventional operation in the art, as long as the ultra-thin copper foil can be obtained; there are no special requirements for the specific operation steps, for example, the ultra-thin copper foil can be torn off with tweezers.

[0132] The present invention provides an ultra-thin copper foil prepared by the preparation method of the present invention. The ultra-thin copper foil of the present invention has fine grains, low roughness, and excellent peeling performance.

[0133] According to a preferred embodiment of the present invention, the thickness of the ultra-thin copper foil is 1.5-2.6 um.

[0134] The surface roughness Rz value of the ultra-thin copper foil (away from the release layer) is 0.65-1.0 μm, preferably 0.6-0.75 μm, and more preferably 0.65-0.7 μm.

[0135] According to a preferred embodiment of the present invention, the surface roughness Rz value of the ultra-thin copper foil (close to the peeling layer) is 1.0-1.7 μm, preferably 1.0-1.15 μm, and more preferably 1.05-1.13 μm.

[0136] According to a preferred embodiment of the present invention, the tensile strength of the ultra-thin copper foil is 205-520 MPa, preferably 400-500 MPa, and more preferably 485-500 MPa.

[0137] According to a preferred embodiment of the present invention, the elongation of the ultra-thin copper foil is 0.5-2.0%, preferably 1.5-2.0%, and more preferably 1.6-2.0%.

[0138] According to a preferred embodiment of the present invention, the peel strength between the ultra-thin copper foil and the composite layer carrier copper foil before lamination at room temperature is 0.1-0.7 N / cm, preferably 0.5-0.65 N / cm, and more preferably 0.55-0.65 N / cm.

[0139] According to a preferred embodiment of the present invention, the peel strength of the ultra-thin copper foil and the composite layer carrier copper foil after pressing at 180-240° C. is 0.2-0.8 N / cm, preferably 0.6-0.8 N / cm, and more preferably 0.7-0.8 N / cm.

[0140] The present invention will be described in detail below through examples. It is necessary to point out that the following examples are only used to further illustrate the present invention and are not to be construed as limiting the scope of protection of the present invention. Those skilled in the art may make some non-essential improvements and adjustments to the present invention based on the above-mentioned content of the present invention.

[0141] In the following examples and comparative examples, if no specific experimental steps or conditions are specified, the experiments were carried out according to the conventional experimental steps or conditions described in the literature in the field. The reagents or instruments used, if the manufacturer is not specified, are all commercially available conventional reagents.

[0142] In the Examples and Comparative Examples,

[0143] Copper foil was purchased from Anhui Tongguan Copper Foil Co., Ltd.

[0144] The thickness of copper foil and ultra-thin copper foil is measured according to GB / T5230-1995.

[0145] The surface roughness (far from the peeling layer) and surface roughness (close to the peeling layer) of the ultra-thin copper foil are measured according to GB / T5230-1995.

[0146] The tensile strength and elongation of ultra-thin copper foil are measured using ASTM D638-22.

[0147] The peel strength of the ultra-thin copper foil and the composite layer carrier copper foil before pressing at room temperature (room temperature peel strength) and the peel strength of the ultra-thin copper foil and the composite layer carrier copper foil after pressing at 180-240°C (high temperature peel strength) are measured according to GB / T5230-1995.

[0148] In the present invention, scanning electron microscope (SEM) images of cross sections of the ultra-thin copper foil (deposition surface on the peeling layer), the ultra-thin copper foil (laminated peeling layer surface), and the ultra-thin copper foil with a carrier were measured using a TESCAN scanning electron microscope.

[0149] In the present invention, the scanning electron microscope (SEM)-energy dispersive spectrophotometer (EDS) image of the ultra-thin copper foil (laminated peeling layer) is measured by a TESCAN scanning electron microscope.

[0150] Table 1 shows the performance test results of the ultra-thin copper foils produced in the examples and comparative examples.

[0151] Example 1

[0152] (1) Pretreatment

[0153] Degreasing: Immerse a 32μm thick copper foil in a degreasing solution containing 4wt% NaOH, 4.5wt% Na2CO3, and 6.5wt% Na3PO4·12H2O for 30s, and control the degreasing temperature at 50℃.

[0154] Pickling: Immerse the degreased copper foil in a solution containing 5wt% nitric acid and 10wt% phosphoric acid at 25°C for 20s.

[0155] (2) Preparation of composite layer carrier copper foil

[0156] Nickel plating: The polished surface of the copper foil after degreasing and pickling was used as the cathode and the iridium-plated titanium plate was used as the anode. The nickel layer was electrolytically deposited in a nickel plating solution containing 235 g / L NiSO4·6H2O, 335 g / L H3BO3, 25 g / L Na2SO4, 20 g / L NaCl, 0.2 g / L thiourea, 0.5 g / L SDS, and 1.5 g / L saccharin sodium. The pH was adjusted to 4 and the current density was set to 10 A / dm 2 , solution temperature 25℃, electroplating time 12s.

[0157] Immersion plating of organic layer: Immerse the copper foil coated with nickel in an aqueous solution containing 5 g / L tetrazole at a temperature of 25°C for 30 seconds. Dry the immersed copper foil (temperature of 180°C for 5 seconds).

[0158] (3) Preparation of ultra-thin copper foil with carrier

[0159] The composite layer of the composite layer carrier copper foil in (2) was used as the cathode, and the iridium-plated titanium plate was used as the anode. The thin copper foil was electroplated in a copper plating solution containing 100 g / L CuSO4·5H2O, 120 g / L H2SO4, 20 mg / L NaCl, 15 mg / L SPS, 20 mg / L collagen, 15 mg / L PEG, and 4 mg / L sodium thiopropane sulfonate. The current density was set to 10 A / dm 2 , solution temperature is 25℃, and electroplating time is 81s.

[0160] (4) Preparation of ultra-thin copper foil

[0161] The composite layer carrier copper foil is removed from the ultra-thin copper foil with carrier dried in (3) using tweezers.

[0162] Example 2

[0163] Steps (1)(3)(4) are consistent with those in Example 1.

[0164] (2) Preparation of composite layer carrier copper foil

[0165] Nickel plating: The polished surface of the copper foil after degreasing and pickling was used as the cathode. The nickel layer was electrolytically deposited in a nickel plating solution containing 35 g / L NiSO4·6H2O2, 35 g / L H3BO3, 25 g / L Na2SO4, 20 g / L NaCl, 0.2 g / L thiourea, 0.5 g / L SDS, and 1 g / L sodium saccharin. The pH was adjusted to 5 and the current density was set to 10 A / dm 2 , solution temperature 25℃, electroplating time 12s.

[0166] Immersion plating of organic layer: Immerse the copper foil coated with nickel in an aqueous solution containing 5.5 g / L of 5-methylthiotetrazole at a temperature of 25°C for 25 seconds. Dry the immersed copper foil (temperature of 190°C for 4 seconds) coated with nickel.

[0167] Example 3

[0168] (1) Pretreatment

[0169] Degreasing: Immerse a 35 μm thick copper foil in a degreasing solution containing 4 wt% NaOH, 4.5 wt% Na2CO3, and 6.5 wt% Na3PO4·12H2O for 30 s, and control the degreasing temperature at 50°C.

[0170] Pickling: Immerse the degreased copper foil in a solution containing 10 wt% nitric acid and 5 wt% phosphoric acid at 25°C for 10 seconds.

[0171] (2) Preparation of composite layer carrier copper foil

[0172] Nickel plating: The polished surface of the copper foil after degreasing and pickling was used as the cathode. The nickel layer was electrolytically deposited in a nickel plating solution containing 195 g / L NiSO4·6H2O, 25 g / L H3BO3, 26 g / L Na2SO4, 20 g / L NaCl, 0.2 g / L ethylenethiourea, 0.5 g / L SDS, and 1 g / L sodium saccharin. The pH was adjusted to 6 and the current density was set to 15 A / dm 2 , solution temperature 25℃, electroplating time 10s.

[0173] Immersion plating of organic layer: The copper foil coated with nickel layer was immersed in an aqueous solution containing 7 g / L of 5-methyltetrazole at a solution temperature of 25°C for 35 seconds. The immersed copper foil coated with nickel layer was dried (at a temperature of 180°C for 4 seconds).

[0174] (3) Preparation of ultra-thin copper foil with carrier

[0175] The composite layer of the composite layer carrier copper foil in (2) was used as the cathode and the iridium-plated titanium plate was used as the anode. The extremely thin copper foil was electrolytically deposited in a copper plating solution containing 100 g / L CuSO4·5H2O, 120 g / L H2SO4, 20 mg / L NaCl, 15 mg / L SPS, 20 mg / L collagen, 15 mg / L PEG, and 4 mg / L sodium thiopropane sulfonate. The current density was set at 20 A / dm 2 , solution temperature is 25℃, and electroplating time is 42s.

[0176] (4) Preparation of ultra-thin copper foil

[0177] The composite layer carrier copper foil is removed from the ultra-thin copper foil with carrier dried in (3) using tweezers.

[0178] Example 4

[0179] Steps (1)(3)(4) are consistent with those in Example 3.

[0180] (2) Preparation of composite layer carrier copper foil

[0181] Nickel plating: The polished surface of the copper foil after degreasing and pickling was used as the cathode. The nickel layer was electrolytically deposited in a nickel plating solution containing 195 g / L NiSO4·6H2O, 25 g / L H3BO3, 26 g / L Na2SO4, 27 g / L NaCl, 0.2 g / L ethylenethiourea, 0.8 g / L SDS, and 1.2 g / L sodium saccharin. The pH was adjusted to 5 and the current density was set to 15 A / dm 2 , solution temperature 25℃, electroplating time 11s.

[0182] Immersion plating of organic layer: The copper foil coated with nickel layer was immersed in an aqueous solution containing 5.5 g / L of 5-mercapto-1-methyltetrazole at a temperature of 25°C and an immersion plating time of 25 seconds. The immersed copper foil coated with nickel layer was dried (at a temperature of 180°C for 4 seconds).

[0183] Example 5

[0184] Steps (1)(3)(4) are consistent with those in Example 3.

[0185] (2) Preparation of composite layer carrier copper foil

[0186] Nickel plating: The polished surface of the copper foil after degreasing and pickling was used as the cathode. The nickel layer was electrolytically deposited in a nickel plating solution containing 195 g / L NiSO4·6H2O, 25 g / L H3BO3, 26 g / L Na2SO4, 27 g / L NaCl, 0.2 g / L ethylenethiourea, 0.5 g / L SDS, and 0.5 g / L sodium saccharin. The pH was adjusted to 4 and the current density was set to 15 A / dm 2 , solution temperature 25℃, electroplating time 9s.

[0187] Immersion plating of organic layer: Immerse the copper foil coated with nickel in an aqueous solution containing 5.5 g / L of 1H-tetrazole-5-acetic acid at a temperature of 25°C for 40 seconds. Dry the immersed copper foil (temperature of 180°C for 4 seconds) coated with nickel.

[0188] Example 6

[0189] (1) Pretreatment

[0190] Degreasing: Immerse 18μm thick copper foil in a degreasing solution containing 5wt% NaOH, 5wt% Na2CO3, and 5wt% Na3PO4·12H2O for 30s, and control the degreasing temperature at 50℃.

[0191] Pickling: Immerse the degreased copper foil in a solution containing 10 wt% concentrated nitric acid and 10 wt% phosphoric acid at 25°C for 30 seconds.

[0192] (2) Preparation of composite layer carrier copper foil

[0193] Nickel plating: The polished surface of the copper foil after degreasing and pickling was used as the cathode. The nickel layer was electrolytically deposited in a nickel plating solution containing 15 g / L NiSO4·6H2O2, 40 g / L H3BO3, 20 g / L Na2SO4, 25 g / L NaCl, 0.5 g / L thiourea, 0.5 g / L SDS, and 1.5 g / L saccharin sodium. The pH was adjusted to 3 and the current density was set to 5 A / dm 2 , solution temperature 25℃, electroplating time 24s.

[0194] Immersion plating of organic layer: The copper foil coated with nickel layer was immersed in an aqueous solution containing 6 g / L of 5-aminotetrazole at a solution temperature of 25°C for 15 seconds. The immersed copper foil coated with nickel layer was dried (at a temperature of 180°C for 5 seconds).

[0195] (3) Preparation of ultra-thin copper foil with carrier

[0196] The composite layer of the composite layer carrier copper foil in (2) was used as the cathode, and the iridium-plated titanium plate was used as the anode. The copper foil was electrolytically deposited in a copper plating solution containing 100 g / L CuSO4·5H2O, 100 g / L H2SO4, 20 mg / L NaCl, 15 mg / L SPS, 15 mg / L collagen, 20 mg / L PEG, and 5 mg / L sodium thiopropane sulfonate. The current density was set to 15 A / dm 2 , solution temperature is 25℃, and electroplating time is 55s.

[0197] (4) Preparation of ultra-thin copper foil

[0198] The composite layer carrier copper foil is removed from the ultra-thin copper foil with carrier dried in (3) using tweezers.

[0199] Example 7

[0200] Steps (1)(3)(4) are consistent with those in Example 6.

[0201] (2) Preparation of composite layer carrier copper foil

[0202] Nickel plating: The polished surface of the copper foil after degreasing and pickling was used as the cathode. The nickel layer was electrolytically deposited in a nickel plating solution containing 15 g / L NiSO4·6H2O2, 40 g / L H3BO3, 20 g / L Na2SO4, 25 g / L NaCl, 0.5 g / L thiourea, 1.5 g / L SDS, and 0.5 g / L sodium saccharin. The pH was adjusted to 4 and the current density was set to 5 A / dm 2 , solution temperature 25℃, electroplating time 20s.

[0203] Immersion plating of organic layer: The copper foil coated with nickel layer was immersed in an aqueous solution containing 4.5 g / L of 5-ethylthiotetrazole at a solution temperature of 25°C for 30 seconds. The immersed copper foil coated with nickel layer was dried (at a temperature of 180°C for 5 seconds).

[0204] Example 8

[0205] Steps (1)(3)(4) are consistent with those in Example 6.

[0206] (2) Preparation of composite layer carrier copper foil

[0207] Nickel plating: the same as in Example 6.

[0208] Immersion plating of organic layer: The copper foil coated with nickel layer was immersed in an aqueous solution containing 6 g / L of 5,5-tetrazolyl diamine salt at a solution temperature of 25°C and an immersion plating time of 15 seconds. The immersed copper foil coated with nickel layer was dried (temperature of 180°C for 5 seconds).

[0209] Example 9

[0210] Steps (1)(3)(4) are consistent with those in Example 6.

[0211] (2) Preparation of composite layer carrier copper foil

[0212] Nickel plating: the same as in Example 6.

[0213] Immersion plating of organic layer: The copper foil coated with nickel layer was immersed in an aqueous solution containing 1 g / L samarium nitrate and 6 g / L 5,5-tetrazolyl diamine salt, the pH was adjusted to 4.3, the solution temperature was 25 ° C, the immersion time was 15 s, and the immersed copper foil coated with nickel layer was dried (temperature was 180 ° C, time was 5 s).

[0214] Example 10

[0215] Steps (1)(3)(4) are consistent with those in Example 6.

[0216] (2) Preparation of composite layer carrier copper foil

[0217] Nickel plating: the same as in Example 6.

[0218] Immersion plating of organic layer: The copper foil coated with nickel layer was immersed in an aqueous solution containing 1 g / L dysprosium nitrate and 6 g / L 5,5-tetrazolyl diamine salt, and the pH was adjusted to 4.5 with acetic acid. The solution temperature was 25 ° C and the immersion time was 15 s. The immersed copper foil coated with nickel layer was dried (temperature was 180 ° C, time was 5 s).

[0219] Figure 1This is a scanning electron microscope (SEM) image (magnified 10,000 times) of the ultra-thin copper foil (deposition surface above the peeling layer) of this embodiment. It can be seen that the roughness of the matte surface of the ultra-thin copper foil is low, and the surface particles are fine and smooth. Figure 2 This is a scanning electron microscope (SEM) image (magnified 10,000 times) of the ultra-thin copper foil (laminated and peeled surface) of this embodiment. It can be seen that the smooth surface of the ultra-thin copper foil has dense particles or protrusions and a high degree of roughness. Figure 3 This is a scanning electron microscope (SEM)-energy dispersive spectrometer (EDS) image of the ultra-thin copper foil (laminated and peeled surface) of this example. It can be seen that the ultra-thin copper foil has a clean surface and no nickel particles remain on the ultra-thin foil after peeling. Figure 4 This is a scanning electron microscope (SEM) image of the cross section of the ultra-thin copper foil with a carrier of this embodiment (magnified 10,000 times), from which it can be seen that the thickness of the ultra-thin copper foil is uniform.

[0220] Example 11

[0221] Steps (1)(3)(4) are consistent with those in Example 6.

[0222] (2) Preparation of composite layer carrier copper foil

[0223] Nickel plating: the same as in Example 6.

[0224] Immersion plating of organic layer: The copper foil coated with nickel layer was immersed in an aqueous solution containing 2.5 g / L tetrazole and 3.5 g / L 1H-tetrazole-5-acetic acid, with a mass ratio of tetrazole to 1H-tetrazole-5-acetic acid of 3:7. The solution temperature was 25 ° C, and the immersion plating time was 15 s. The immersed copper foil coated with nickel layer was dried (temperature was 180 ° C, time was 5 s).

[0225] Example 12

[0226] Steps (1)(3)(4) are consistent with those in Example 6.

[0227] (2) Preparation of composite layer carrier copper foil

[0228] Nickel plating: the same as in Example 6.

[0229] Immersion plating of organic layer: Immerse the copper foil coated with nickel in an aqueous solution containing 2 g / L of 5,5-tetrazole diamine salt and 4 g / L of 5-mercapto-1-methyltetrazole, with a mass ratio of 5,5-tetrazole diamine salt to 5-mercapto-1-methyltetrazole being 2:3. The solution temperature is 25°C and the immersion plating time is 15 seconds. The immersed copper foil coated with nickel is dried (temperature is 180°C, time is 5 seconds).

[0230] Comparative Example 1

[0231] Steps (1) (3) (4) are consistent with those in Example 1, and step (2) is consistent with the nickel plating step in Example 1, without immersion plating of the organic layer.

[0232] Comparative Example 2

[0233] Steps (1)(3)(4) are consistent with those in Example 3.

[0234] (2) Preparation of composite layer carrier copper foil

[0235] Nickel plating: the same as in Example 3.

[0236] Immersion plating of organic layer: Immerse the copper foil coated with nickel in a 7 g / L aqueous solution of 5-benzyltetrazole at a temperature of 25°C for 35 seconds. Dry the immersed copper foil (temperature of 180°C for 4 seconds) coated with nickel.

[0237] Comparative Example 3

[0238] Steps (1)(3)(4) are consistent with those in Example 6.

[0239] (2) Preparation of composite layer carrier copper foil

[0240] Nickel plating: the same as in Example 6.

[0241] Immersion plating of organic layer: Immerse the copper foil coated with nickel in an aqueous solution containing 6 g / L of 5-benzylthiotetrazole at a temperature of 25°C for 15 seconds. Dry the immersed copper foil (temperature of 180°C for 5 seconds) after the nickel coating is applied.

[0242] Comparative Example 4

[0243] Steps (1)(3)(4) are consistent with those in Example 6.

[0244] (2) Preparation of composite layer carrier copper foil

[0245] Nickel plating: the same as in Example 6.

[0246] Immersion plating of organic layer: Immerse the copper foil coated with nickel in an aqueous solution containing 1 g / L samarium nitrate and 6 g / L 2,3,5-triphenyltetrazolium chloride. The solution temperature is 25°C and the immersion time is 15 seconds. The immersed copper foil coated with nickel is dried (temperature is 180°C, time is 5 seconds).

[0247] Comparative Example 5

[0248] Steps (1)(3)(4) are consistent with those in Example 6.

[0249] (2) Preparation of composite layer carrier copper foil

[0250] Nickel plating: the same as in Example 6.

[0251] Immersion plating of organic layer: Immerse the copper foil coated with nickel in an aqueous solution containing 6 g / L imidazole at a temperature of 25°C for 15 seconds. Dry the immersed copper foil (temperature of 180°C for 5 seconds) coated with nickel.

[0252] Comparative Example 6

[0253] Steps (1)(3)(4) are consistent with those in Example 6.

[0254] (2) Preparation of composite layer carrier copper foil

[0255] Nickel plating: the same as in Example 6.

[0256] Immersion plating of organic layer: Immerse the copper foil coated with nickel in an aqueous solution containing 6 g / L of benzotriazole at a solution temperature of 25°C for 15 seconds. Dry the immersed copper foil (temperature of 180°C for 5 seconds) coated with nickel.

[0257] The parameters of the ultra-thin electrolytic copper foils of the above embodiments and comparative examples are listed in Table 1.

[0258] Table 1

[0259]

[0260]

[0261]

[0262] From the implementation results of the above embodiments and comparative examples and the data in Table 1, it can be seen that the ultra-thin copper foil prepared using the technical solution of the present invention achieves good peel strength, low surface roughness, and excellent mechanical properties. As can be seen from Examples 6, 8, 9, and 10, compared with aqueous solutions containing tetrazole compounds, the present invention adds rare earth metals to aqueous solutions containing tetrazole compounds, thereby improving the peel strength and solving the problem of the organic layer as a peeling layer having too low peel strength. As can be seen from Examples 11 and 12, compared with aqueous solutions containing one tetrazole compound, the ultra-thin copper foil prepared from aqueous solutions containing two tetrazole compounds has lower surface roughness, more stable peel strength, and better tensile strength and elongation.

[0263] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, various simple variations of the technical solution of the present invention may be made, including combining the various technical features in any other appropriate manner. These simple variations and combinations should also be regarded as disclosed in the present invention and fall within the scope of protection of the present invention.

Claims

1. A composite layer carrier copper foil, characterized in that: The carrier copper foil comprises a copper foil and a composite layer formed on the smooth surface of the copper foil, wherein the composite layer comprises a nickel layer and an organic layer of a tetrazole compound from the inside to the outside, wherein the tetrazole compound has a structure as shown in the following formula (1): wherein R1 is selected from hydrogen, amino, tetrazole group or a group containing 1-5 carbon atoms; R2 is selected from hydrogen, thiol, amino or a group containing 1-5 carbon atoms, The groups containing 1 to 5 carbon atoms in R1 and R2 are independently selected from C1-C5 alkyl groups, C1-C5 alkyl groups substituted with carboxyl groups, and C1-C5 alkyl groups substituted with thio groups.

2. The carrier copper foil according to claim 1, wherein The organic layer of the tetrazole compound contains a rare earth metal salt; Preferably, the mass ratio of the tetrazole compound to the rare earth metal salt is (0.07-50):1, preferably (0.75-14):1; More preferably, the rare earth metal salt comprises one or more of nitrates, chlorates and sulfates, preferably one or more of lanthanum nitrate, cerium nitrate, samarium nitrate and dysprosium nitrate; and / or The tetrazole compound is selected from one or more of tetrazole, 5-methylthiotetrazole, 5-methyltetrazole, 5-mercapto-1-methyltetrazole, 1H-tetrazole-5-acetic acid, 5-aminotetrazole, 5-ethylthiotetrazole and 5,5-bi-tetrazole diamine salt; Preferably, the tetrazole compound is tetrazole and 1H-tetrazole-5-acetic acid, and the mass ratio of tetrazole to 1H-tetrazole-5-acetic acid is 1:(2-4); or the tetrazole compound is 5,5-tetrazole diamine salt and 5-mercapto-1-methyltetrazole, and the mass ratio of 5,5-tetrazole diamine salt to 5-mercapto-1-methyltetrazole is 1:(1-3); and / or The nickel layer is formed by electroplating; and / or The organic layer is formed by immersing or coating an aqueous solution containing a tetrazole compound and optionally a rare earth metal salt.

3. A method for preparing a composite layer carrier copper foil, characterized in that: The method includes: Electroplating the smooth surface of the copper foil: Electrodepositing in a nickel plating solution to form a nickel layer; Then, immersion plating is performed: an organic layer is formed by immersing or coating an aqueous solution containing a tetrazole compound, wherein the tetrazole compound has a structure shown in the following formula (1): wherein R1 is selected from hydrogen, amino, tetrazole group or a group containing 1-5 carbon atoms; R2 is selected from hydrogen, thiol, amino or a group containing 1-5 carbon atoms, The groups containing 1 to 5 carbon atoms in R1 and R2 are independently selected from C1-C5 alkyl groups, C1-C5 alkyl groups substituted with carboxyl groups, and C1-C5 alkyl groups substituted with thio groups.

4. The method according to claim 3, wherein: During immersion plating, The aqueous solution containing the tetrazole compound contains a rare earth metal salt; Preferably, The content of rare earth metal salt is 0.2-7 g / L, preferably 0.5-4 g / L; and / or The rare earth metal salt includes one or more of nitrates, chlorates and sulfates, preferably one or more of lanthanum nitrate, cerium nitrate, samarium nitrate and dysprosium nitrate; and / or The aqueous solution containing tetrazole compounds has a content of 0.5-10 g / L, preferably 3-7 g / L; and / or The tetrazole compound is selected from one or more of tetrazole, 5-methylthiotetrazole, 5-methyltetrazole, 5-mercapto-1-methyltetrazole, 1H-tetrazole-5-acetic acid, 5-aminotetrazole, 5-ethylthiotetrazole and 5,5-bi-tetrazole diamine salt; Preferably, the tetrazole compound is tetrazole and 1H-tetrazole-5-acetic acid, and the mass ratio of tetrazole to 1H-tetrazole-5-acetic acid is 1:(2-4); or the tetrazole compound is 5,5-tetrazolyl diamine salt and 5-mercapto-1-methyltetrazole, and the mass ratio of 5,5-tetrazolyl diamine salt to 5-mercapto-1-methyltetrazole is 1:(1-3); and / or The conditions for the immersion plating include: The immersion temperature is 15-25°C; and / or The immersion time is 5-60s.

5. The method according to claim 3 or 4, wherein: During electroplating, The nickel plating solution contains a nickel source, a pH buffer, a sulfate, a chloride salt and a nickel plating additive; Preferably, The nickel source is a soluble nickel salt, preferably one or more of nickel sulfate, nickel chloride, nickel sulfamate, nickel carbonate, nickel nitrate, and nickel acetate; more preferably nickel sulfate; and / or The concentration of the nickel source is 150-275 g / L; and / or The pH buffer comprises one or more of boric acid, citric acid, sodium citrate, sodium acetate, acetic acid, NH2SO3H, sodium dihydrogen phosphate, phosphoric acid, sodium fluoroborate, preferably boric acid; and / or The concentration of the pH buffer is 20-60 g / L; and / or The sulfate includes one or more of sodium sulfate, magnesium sulfate, and ammonium sulfate, preferably sodium sulfate; and / or The concentration of the sulfate is 20-40 g / L; and / or The chloride salt includes one or more of sodium chloride and potassium chloride, preferably sodium chloride; The concentration of the chloride salt is 15-30 g / L; and / or The nickel plating additive includes one or more of thiourea, ethylenethiourea, SDS, sodium saccharin, butynediol, coumarin, 1,5-naphthalene disulfonic acid, and pinene; preferably, The nickel plating additive is thiourea, SDS and sodium saccharin, and the mass ratio of thiourea, SDS and sodium saccharin is 1:(1-3):(1-7.5); or the nickel plating additive is ethylene thiourea, SDS and sodium saccharin, and the mass ratio of ethylene thiourea, SDS and sodium saccharin is 1:(2.5-4):(2.5-6); and / or The concentration of the nickel plating additive is 0.1-4 g / L; and / or The electroplating conditions include: Current density is 5-35A / dm 2 and / or The pH range for electroplating is 3-8; and / or The plating temperature is 25-65°C; and / or The electroplating time is 5-45s.

6. A composite layer carrier copper foil prepared by the method according to any one of claims 3 to 5.

7. A method for realizing easy peeling of ultra-thin copper foil with carrier on composite layer, characterized in that: The method comprises: in a copper plating solution, electroplating the composite surface of the composite layer carrier copper foil according to claim 1, 2 or 6 to form an ultra-thin copper foil, thereby obtaining an ultra-thin copper foil with a carrier.

8. The method according to claim 7, wherein: The copper plating solution contains a copper source, sulfuric acid, a chloride ion source and a copper plating additive; Preferably, The concentration of the copper source is 20-200 g / L; and / or The concentration of the sulfuric acid is 20-125 g / L; and / or The concentration of the chloride ion source is 15-50 mg / L; and / or The concentration of the copper plating additive is 2-70 mg / L; and / or The copper plating additives include one or more of SPS, collagen, PEG, sodium alcoholthiopropane sulfonate, HEC, allyl polyoxyethylene ether, and sodium phenyl disulfide propane sulfonate; preferably, The copper plating additives are SPS, collagen, PEG and sodium thiopropane sulfonate, and the mass ratio of SPS, collagen, PEG and sodium thiopropane sulfonate is (3-4): (3-5): (3-4): 1; and / or The copper source is a soluble copper salt, preferably copper sulfate; and / or The chloride ion source includes one or more of HCl and NaCl; and / or The conditions for the electrodeposition include: Current density is 5-35A / dm 2 and / or The plating temperature is 25-55°C; and / or The deposition time is 40-200s.

9. A method for preparing an ultra-thin copper foil, characterized in that: An ultra-thin copper foil with a carrier is obtained by the method according to claim 7 or 8, and the ultra-thin copper foil with a carrier is mechanically peeled off to obtain an ultra-thin copper foil.

10. The ultra-thin copper foil prepared by the method of claim 9; preferably, The thickness of the ultra-thin copper foil is 1.5-2.6 μm; and / or The surface roughness Rz value of the ultra-thin copper foil (away from the peeling layer) is 0.65-1.0 μm, preferably 0.6-0.75 μm, more preferably 0.65-0.7 μm; and / or The surface roughness Rz value of the ultra-thin copper foil (near the peeling layer) is 1.0-1.7 μm, preferably 1.0-1.15 μm, more preferably 1.05-1.13 μm; and / or The tensile strength of the ultra-thin copper foil is 205-520 MPa, preferably 400-500 MPa, more preferably 485-500 MPa; and / or The elongation of the ultra-thin copper foil is 0.5-2.0%, preferably 1.5-2.0%, more preferably 1.6-2.0%; and / or The peel strength of the ultra-thin copper foil and the composite layer carrier copper foil before lamination at room temperature is 0.1-0.7 N / cm, preferably 0.5-0.65 N / cm, more preferably 0.55-0.65 N / cm; and / or The peel strength of the ultra-thin copper foil and the composite layer carrier copper foil after being pressed at 180-240° C. is 0.2-0.8 N / cm, preferably 0.6-0.8 N / cm, and more preferably 0.7-0.8 N / cm.

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