A multi-layer composite copper foil and a manufacturing process thereof

Abstract

The application relates to the technical field of semiconductor wafer materials, and discloses a multilayer composite oxidation-resistant copper foil and a manufacturing process thereof, which comprises, from inside to outside, a base layer, a buffer layer, an oxidation-resistant layer and a protective layer; the base layer is high-purity electrolytic copper with a purity of not less than 99.99% and a thickness of 10-50 microns; the buffer layer is a nickel-phosphorus alloy coated with a nitrogen-doped graphene@carbon nanotube core-shell structure and has a thickness of 0.5-2 microns; the oxidation-resistant layer is a nanoscale copper oxide@zeolite imidazolate framework material-8 core-shell structure, and the nanoscale copper oxide particles have an average particle size of 5-50 nm; and the protective layer is a poly-p-xylylene film with a thickness of 0.1-0.5 microns. The functional layers are closely combined and cooperated with each other, the buffer layer relieves thermal stress and provides stable support for the oxidation-resistant layer and the protective layer, the multilayer composite structure realizes performance superposition and optimization, and the high-performance and long-service-life requirement of copper foils in the field of electronic devices and the like is met.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor wafer materials, in particular to a multilayer composite oxidation-resistant copper foil and a manufacturing process thereof. BACKGROUND

[0002] In the process of manufacturing semiconductor wafers, copper foil is widely used as an important conductive and heat-dissipating material. However, the traditional copper foil faces many problems in the process of use, especially in complex environments such as high temperature and high humidity. The surface of the copper foil is prone to oxidation, which leads to a decrease in its conductivity and an increase in its resistance, thereby affecting the performance and reliability of semiconductor devices. In addition, with the continuous development of semiconductor technology, higher requirements are put forward for the flexibility, mechanical strength and bonding force of copper foil with semiconductor wafers. The existing single-structure copper foil or simply treated copper foil has been difficult to meet the growing demand of the semiconductor industry. Therefore, it is of great practical significance to develop a multilayer composite copper foil with excellent oxidation resistance and good comprehensive performance and an efficient manufacturing process thereof. SUMMARY

[0003] (I) Technical problems to be solved

[0004] In view of the deficiencies of the prior art, the present application provides a multilayer composite oxidation-resistant copper foil and a manufacturing process thereof.

[0005] (II) Technical solutions

[0006] To achieve the above-mentioned purpose, the present application provides the following technical solutions: a multilayer composite oxidation-resistant copper foil, characterized in that it comprises, from the inside to the outside, a base layer, a buffer layer, an oxidation-resistant layer and a protective layer; the base layer is high-purity electrolytic copper with a purity of not less than 99.99% and a thickness of 10-50 μm; the buffer layer is a nickel-phosphorus alloy coated with a nitrogen-doped graphene@carbon nanotube core-shell structure, with a thickness of 0.5-2 μm; the oxidation-resistant functional layer is a nanoscale copper oxide@zeolite imidazolate framework material-8 core-shell structure, with nanoscale copper oxide particles having an average particle size of 5-50 nm; and the protective layer is a poly-p-xylylene film with a thickness of 0.1-0.5 μm.

[0007] Further, the base layer preparation method comprises the following steps: placing copper sulfate electrolyte in an electrolytic cell, using a titanium roller as a cathode and a lead-silver alloy as an anode placed in the electrolyte, and depositing copper foil on the surface of the cathode titanium roller under the action of a direct current electric field.

[0008] Further, the electrolyte comprises 180-220 g / L copper sulfate and 50-80 g / L sulfuric acid, the electrolysis temperature is 50-60℃, and the current density is 20-40 A / dm 2 .

[0009] Further, the preparation method of the buffer layer comprises the following steps:

[0010] A1, the purity of nickel powder ≥99.9% and the purity of red phosphorus powder ≥99.5% are weighed according to the proportion of nickel content 85-95% and phosphorus content 5-15%, the raw materials are put into magnesia crucible by using vacuum induction melting furnace, vacuum is extracted to 10 -3 Pa, high-purity argon gas is filled for protection, heated to 1500-1600℃ at a heating rate of 10-15℃ / min, and kept for 20-30min, the molten alloy liquid is flowed into a high-pressure nitrogen gas atomization device through the bottom nozzle, the nitrogen gas pressure is set to 5-10MPa, the alloy liquid is atomized into fine particles, and the nickel-phosphorus alloy powder is collected after cooling; an air flow classifier is used for screening the alloy powder, and the particles with a particle size in the range of 1-10μm are collected to obtain the nickel-phosphorus alloy powder;

[0011] A2, the nickel-phosphorus alloy powder is put into a chemical vapor deposition reaction furnace, heated to 1000-1200℃ in an argon atmosphere, hydrogen gas is introduced at a flow rate of 30-50sccm, kept for 30-60min, a mixed gas of methane and hydrogen is introduced, the flow rate of methane is 10-20sccm, the flow rate of hydrogen is 30-50sccm, kept for 10-20min, the methane is closed, and the temperature is lowered to room temperature in a hydrogen atmosphere to obtain graphene-coated nickel-phosphorus alloy powder;

[0012] A3, the graphene-coated nickel-phosphorus alloy powder is put into the chemical vapor deposition reaction furnace again, heated to 750-850℃ in an argon atmosphere, 0.05-0.1g / mL ferrocene / dimethylbenzene solution is introduced into the reaction furnace through argon gas at a flow rate of 80-100sccm, kept for 30-60min, the ferrocene solution is closed, and the temperature is lowered to room temperature in an argon atmosphere to obtain graphene@carbon nanotube core-shell structure-coated nickel-phosphorus alloy powder;

[0013] A4, the graphene@carbon nanotube core-shell structure-coated nickel-phosphorus alloy powder is mixed with a binder uniformly, a hot-pressing process is adopted, the mixture is pressed into a buffer layer film with a thickness of 0.5-2μm under the conditions of a temperature of 300-400℃ and a pressure of 5-10MPa, then the buffer layer film is attached to the surface of the base copper foil, the binder is made to play a role by heating and curing, and firm combination of the buffer layer and the base is realized;

[0014] A5, the above sample is put into a tube furnace, heated to 800-1000℃ in an argon atmosphere, a mixed gas of ammonia and argon is introduced, the flow rate of ammonia is 30-50sccm, the flow rate of argon is 80-100sccm, kept for 30-60min, the ammonia is closed, and the temperature is lowered to room temperature in an argon atmosphere to obtain a nitrogen-doped graphene@carbon nanotube core-shell structure-coated nickel-phosphorus alloy buffer layer.

[0015] Further, the binder is one of an epoxy resin, a phenol resin, and a polyimide.

[0016] Further, the preparation method of the anti-oxidation layer comprises the following steps:

[0017] B1, dissolving copper nitrate in ethylene glycol methyl ether to form a solution with a concentration of 0.1-0.3 mol / L, then adding citric acid as a complexing agent, stirring uniformly, slowly adding ammonia water at 60-80℃, adjusting the pH value of the solution to 7-8, continuously stirring for 10-30 min, forming a stable sol, drying the sol at 80-100℃ to obtain a dry gel, and calcining the dry gel at 400-600℃ for 2-4 h to obtain nano-sized copper oxide particles;

[0018] B2, dispersing the nano-sized copper oxide particles in ethanol, adding 3-aminopropyl triethoxysilane in an amount of 3-5% of the mass of the nano-sized copper oxide particles, reacting at 50-70℃ for 1-3 h under a nitrogen atmosphere, centrifuging, washing with ethanol, and vacuum drying at 60-80℃ for 4-8 h;

[0019] B3, dispersing the surface-treated nano-sized copper oxide particles in methanol, adding zinc nitrate in an amount of 20-30% of the mass of the nano-sized copper oxide particles and 2-methylimidazole in an amount of 50-60%, stirring and reacting at room temperature for 12-24 h, mixing with polyetheramine D230 at a mass ratio of 5-7:1, adding toluene to form a solution with a solid content of 10%, and treating at a high speed of 1000-2000 r / min and under ultrasonic conditions of 200-350 W for 10-30 min to obtain a precursor solution of the anti-oxidation functional layer;

[0020] B4, immersing the copper foil plated with the buffer layer in the precursor solution of the anti-oxidation functional layer, uniformly coating the precursor solution on the surface of the buffer layer by dip coating, and drying at 80-120℃ to form an anti-oxidation layer with uniform thickness.

[0021] Further, the preparation method of the protective layer comprises the following steps:

[0022] Placing the copper foil treated by the anti-oxidation layer into a vacuum deposition device, placing p-xylene dimer into a crucible of a sublimation furnace, loading an amount not more than 2 / 3 of the volume of the crucible, heating to 150-200℃ and maintaining for 10-30 min, transporting the sublimated gas to a cracking furnace by nitrogen, then introducing into a deposition chamber at 650-750℃ and maintaining for 1-3 min, and depositing and polymerizing to form a p-xylene film on the surface of the copper foil treated by the anti-oxidation layer.

[0023] (Three) Beneficial technical effects

[0024] The nanoscale copper oxide@zeolite imidazolate framework-8 core-shell structure in the antioxidant layer forms a physical barrier, effectively preventing the contact of oxygen, water vapor and other corrosive substances with the copper foil, and the nanoscale copper oxide plays an antioxidant role, and the two are combined to significantly improve the antioxidant capacity of the copper foil; the parylene film protective layer structure is dense, further isolates the external oxidizing medium, and prolongs the antioxidant life of the copper foil.

[0025] The nitrogen-doped graphene@carbon nanotube core-shell structure coated nickel-phosphorus alloy buffer layer utilizes the excellent thermal conductivity and flexibility of graphene and carbon nanotubes to relieve the thermal stress of the copper foil when the temperature changes, and reduce the structural damage caused by the difference in the thermal expansion coefficient; at the same time, the buffer layer can effectively disperse heat and avoid local overheating, thereby improving the stability of the copper foil in a high-temperature environment.

[0026] The high-purity base layer electrolytic copper ensures a good conductive basis; the parylene film protective layer has low dielectric constant and small dielectric loss, and can stably transmit electrical signals in a high-frequency environment, thereby reducing signal attenuation and distortion.

[0027] The functional layers are closely combined and cooperated, the buffer layer relieves the thermal stress, and provides stable support for the antioxidant layer and the protective layer; the multi-layer composite structure realizes the superposition and optimization of performance, and meets the demand for high performance and long life of the copper foil in the field of electronic devices. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0029] The formula components of the multi-layer composite antioxidant copper foil of the present application are all commercially available unless otherwise specified.

[0030] Embodiment 1

[0031] A multi-layer composite antioxidant copper foil, characterized in that it comprises, from inside to outside, a base layer, a buffer layer, an antioxidant layer and a protective layer; the base layer is high-purity electrolytic copper with a purity of not less than 99.99% and a thickness of 10 μm; the buffer layer is a nitrogen-doped graphene@carbon nanotube core-shell structure coated nickel-phosphorus alloy with a thickness of 0.5 μm; the antioxidant functional layer is a nanoscale copper oxide@zeolite imidazolate framework-8 core-shell structure, and the average particle size of the nanoscale copper oxide particles is 5-50 nm; and the protective layer is a parylene film with a thickness of 0.1 μm.

[0032] The electrolyte comprises 180 g / L copper sulfate and 50 g / L sulfuric acid, the electrolysis temperature is 50 DEG C, and the current density is 20 A / dm 2 .

[0033] The binder is an epoxy resin.

[0034] The base layer preparation method comprises the following steps: placing a copper sulfate electrolyte in an electrolytic cell, using a titanium roller as a cathode and a lead-silver alloy as an anode, and depositing copper foil on the surface of the cathode titanium roller under the action of a direct current electric field.

[0035] The buffer layer preparation method comprises the following steps:

[0036] A1, weighing nickel powder with a purity of ≥99.9% and red phosphorus powder with a purity of ≥99.5% according to a ratio of 85% nickel content and 15% phosphorus content, placing the raw materials in a magnesia crucible by using a vacuum induction melting furnace, vacuumizing to 10 Pa, filling high-purity argon for protection, heating to 1500 DEG C at a heating rate of 10 DEG C / min, keeping for 20 min, flowing the molten alloy liquid into a high-pressure nitrogen atomization device through a bottom nozzle, setting the nitrogen pressure to 5 MPa, atomizing the alloy liquid into fine particles, collecting the nickel-phosphorus alloy powder after cooling, and screening the alloy powder by using an air flow classifier to collect particles with a particle size in a range of 1-10 μm to obtain the nickel-phosphorus alloy powder. -3 Pa, filling high-purity argon for protection, heating to 1500 DEG C at a heating rate of 10 DEG C / min, keeping for 20 min, flowing the molten alloy liquid into a high-pressure nitrogen atomization device through a bottom nozzle, setting the nitrogen pressure to 5 MPa, atomizing the alloy liquid into fine particles, collecting the nickel-phosphorus alloy powder after cooling, and screening the alloy powder by using an air flow classifier to collect particles with a particle size in a range of 1-10 μm to obtain the nickel-phosphorus alloy powder.

[0037] A2, placing the nickel-phosphorus alloy powder into a chemical vapor deposition reaction furnace, heating to 1000 DEG C under an argon atmosphere, flowing in hydrogen with a flow rate of 30 sccm and keeping for 30 min, flowing in a mixed gas of methane and hydrogen with a methane flow rate of 10 sccm and a hydrogen flow rate of 30 sccm and keeping for 10 min, closing the methane, and cooling to room temperature under a hydrogen atmosphere to obtain graphene-coated nickel-phosphorus alloy powder.

[0038] A3, placing the graphene-coated nickel-phosphorus alloy powder into the chemical vapor deposition reaction furnace again, heating to 750 DEG C under an argon atmosphere, flowing in 0.05 g / mL ferrocene / dimethylbenzene solution into the reaction furnace through argon with a flow rate of 80 sccm and keeping for 30 min, closing the ferrocene solution, and cooling to room temperature under an argon atmosphere to obtain graphene@carbon nanotube core-shell structure-coated nickel-phosphorus alloy powder.

[0039] A4, uniformly mixing the graphene@carbon nanotube core-shell structure-coated nickel-phosphorus alloy powder with a binder, pressing the mixture into a buffer layer film by using a hot-pressing forming process under the conditions of a temperature of 300 DEG C and a pressure of 5 MPa, then pasting the buffer layer film on the surface of the base layer copper foil, and realizing firm combination of the buffer layer and the base layer by heating and curing to make the binder play a role.

[0040] A5, the sample is placed into a tube furnace, heated to 800℃ under argon atmosphere, mixed gas of ammonia and argon is introduced, ammonia flow is 30sccm, argon flow is 80sccm, and the process is kept for 30min, then ammonia is closed, and the temperature is decreased to room temperature under argon atmosphere, to obtain the nickel-phosphorus alloy buffer layer coated with nitrogen-doped graphene@carbon nanotube core-shell structure.

[0041] The preparation method of the anti-oxidation layer comprises the following steps:

[0042] B1, copper nitrate is dissolved in ethylene glycol methyl ether to form a solution with a concentration of 0.1mol / L, then citric acid is added as a complexing agent, and the solution is stirred uniformly, ammonia water is slowly added dropwise at 60℃, the pH value of the solution is adjusted to 7, and the stirring is continued for 10min, a stable sol is formed, the sol is dried at 80℃ to obtain a dry gel, and the dry gel is calcined at 400℃ for 2h to obtain nano-sized copper oxide particles;

[0043] B2, the nano-sized copper oxide particles are dispersed in ethanol, 3-aminopropyl triethoxysilane is added in an amount of 3% of the mass of the nano-sized copper oxide, and the mixture is reacted at 50℃ under nitrogen atmosphere for 1h, then centrifuged, washed with ethanol, and dried at 60℃ under vacuum for 4h;

[0044] B3, the surface-treated nano-sized copper oxide is dispersed in methanol, zinc nitrate and 2-methyl imidazole are added in amounts of 20% and 50% of the mass of the nano-sized copper oxide respectively, and the mixture is stirred and reacted at room temperature for 12h, then mixed with polyetheramine D230 at a mass ratio of 5:1, toluene is added to form a solution with a solid content of 10%, and the solution is treated under the conditions of high-speed stirring at 1000r / min and ultrasonic wave with a power of 200W for 10min, to obtain a precursor solution of the anti-oxidation functional layer;

[0045] B4, the copper foil coated with the buffer layer is immersed in the precursor solution of the anti-oxidation functional layer, the precursor solution is uniformly coated on the surface of the buffer layer by dip coating, and then dried at 80℃ to form an anti-oxidation layer with uniform thickness.

[0046] The preparation method of the protective layer comprises the following steps:

[0047] The copper foil treated by the anti-oxidation layer is placed into a vacuum deposition device, parylene dimer is placed into a crucible of a sublimation furnace, the loading amount is not more than 2 / 3 of the volume of the crucible, heated to 150℃ and kept for 10min, the sublimated gas is transported to a cracking furnace by nitrogen, then introduced into a deposition chamber at 650℃ and kept for 1min, and then deposited for 10min at a deposition temperature of 40℃, to deposit and polymerize on the surface of the copper foil treated by the anti-oxidation layer to form a parylene film.

[0048] Example 2

[0049] A multi-layer composite anti-oxidation copper foil characterized by comprising, from inside to outside, a base layer, a buffer layer, an anti-oxidation layer and a protective layer; the base layer is high-purity electrolytic copper with a purity of no less than 99.99% and a thickness of 10 microns; the buffer layer is a nickel-phosphorus alloy coated with a nitrogen-doped graphene@carbon nanotube core-shell structure and has a thickness of 0.5 microns; the anti-oxidation functional layer is a nano-sized copper oxide@zeolite imidazolate framework-8 core-shell structure, and the nano-sized copper oxide particles have an average particle size of 5-50 nm; and the protective layer is a parylene film with a thickness of 0.1 microns.

[0050] The electrolyte comprises 200 g / L copper sulfate and 60 g / L sulfuric acid, the electrolysis temperature is 55 DEG C, and the current density is 30 A / dm 2 .

[0051] The binder is a phenolic resin.

[0052] The base layer preparation method comprises the following steps: placing a copper sulfate electrolyte in an electrolytic cell, using a titanium roller as a cathode and a lead-silver alloy as an anode, and depositing copper foil on the surface of the cathode titanium roller under the action of a direct current electric field.

[0053] The buffer layer preparation method comprises the following steps:

[0054] A1, weighing nickel powder with a purity of no less than 99.9% and red phosphorus powder with a purity of no less than 99.5% according to a ratio of 90% nickel content and 10% phosphorus content, placing the raw materials in a magnesia crucible by using a vacuum induction melting furnace, vacuumizing to 10 -3 Pa, filling high-purity argon gas for protection, heating to 1500 DEG C at a heating rate of 15 DEG C / min and keeping for 25 min, flowing the molten alloy liquid into a high-pressure nitrogen gas atomization device through a bottom nozzle, setting the nitrogen gas pressure to 8 MPa, atomizing the alloy liquid into fine particles, collecting the nickel-phosphorus alloy powder after cooling, screening the alloy powder by using an air flow classifier, collecting particles with a particle size in a range of 1-10 microns, and obtaining the nickel-phosphorus alloy powder;

[0055] A2, placing the nickel-phosphorus alloy powder into a chemical vapor deposition reaction furnace, heating to 1100 DEG C under an argon atmosphere, flowing in hydrogen gas with a flow rate of 40 sccm and keeping for 40 min, flowing in a mixed gas of methane and hydrogen, with a methane flow rate of 15 sccm and a hydrogen flow rate of 40 sccm, and keeping for 15 min, closing the methane, and cooling to room temperature under a hydrogen atmosphere, to obtain graphene-coated nickel-phosphorus alloy powder;

[0056] A3, the graphene coated nickel-phosphorus alloy powder is put into the chemical vapor deposition reaction furnace again, heated to 800℃ under argon atmosphere, 0.08g / mL ferrocene / xylene solution is introduced into the reaction furnace by argon with a flow rate of 90sccm, and kept for 40min, then the ferrocene solution is turned off, and the temperature is lowered to room temperature under argon atmosphere, to obtain graphene@carbon nanotube core-shell structure coated nickel-phosphorus alloy powder;

[0057] A4, the graphene@carbon nanotube core-shell structure coated nickel-phosphorus alloy powder is mixed with the binder uniformly, and the mixture is pressed into a buffer layer film under the conditions of temperature 350℃ and pressure 8MPa by using the hot-pressing process, then the buffer layer film is attached to the surface of the base copper foil, and the binder is made to play a role by heating and curing, so as to realize the firm combination of the buffer layer and the base layer;

[0058] A5, the above sample is put into a tube furnace, heated to 900℃ under argon atmosphere, and a mixed gas of ammonia and argon is introduced, the flow rate of ammonia is 40sccm, the flow rate of argon is 90sccm, and kept for 40min, then the ammonia is turned off, and the temperature is lowered to room temperature under argon atmosphere, to obtain a nitrogen-doped graphene@carbon nanotube core-shell structure coated nickel-phosphorus alloy buffer layer.

[0059] The preparation method of the anti-oxidation layer comprises the following steps:

[0060] B1, copper nitrate is dissolved in ethylene glycol methyl ether to form a solution with a concentration of 0.2mol / L, then citric acid is added as a complexing agent, and stirred uniformly, ammonia water is slowly added at 70℃, the pH value of the solution is adjusted to 8, and the stirring is continued for 20min to form a stable sol, the sol is dried at 90℃ to obtain a dry gel, and the dry gel is calcined at 450℃ for 3h to obtain nano-sized copper oxide particles;

[0061] B2, the nano-sized copper oxide particles are dispersed in ethanol, 3-aminopropyl triethoxysilane is added in an amount of 4% of the mass of the nano-sized copper oxide, and reacted at 60℃ under nitrogen atmosphere for 2h, centrifuged, washed with ethanol, and vacuum dried at 70℃ for 6h;

[0062] B3, the surface-treated nano-sized copper oxide is dispersed in methanol, zinc nitrate and 2-methyl imidazole are added in amounts of 25% and 55% of the mass of the nano-sized copper oxide respectively, and stirred at room temperature for 18h, then mixed with polyetheramine D230 at a mass ratio of 6:1, and a toluene solution with a solid content of 10% is formed, and treated under the conditions of high-speed stirring at 1500r / min and ultrasonic wave with a power of 300W for 20min to obtain a precursor solution of the anti-oxidation functional layer;

[0063] B4, the copper foil plated with the buffer layer is immersed into an anti-oxidation functional layer precursor solution, the precursor solution is uniformly coated on the surface of the buffer layer by using a dip coating method, and then the anti-oxidation layer with uniform thickness is formed by drying at 100℃.

[0064] The preparation method of the protective layer comprises the following steps:

[0065] The copper foil treated by the anti-oxidation layer is placed into a vacuum deposition device, the p-xylene dimer is placed into a crucible of a sublimation furnace, the loading amount is not more than 2 / 3 of the volume of the crucible, heating is performed to 180℃, and the temperature is kept for 20 min, the gas sublimated by nitrogen is transported to a cracking furnace, then the copper foil treated by the anti-oxidation layer is introduced into a deposition chamber at 700℃, the temperature is kept for 2 min, and then the deposition is performed for 20 min at a deposition temperature of 50℃, so that the p-xylene film is deposited and polymerized on the surface of the copper foil treated by the anti-oxidation layer.

[0066] Example 3

[0067] A multi-layer composite anti-oxidation copper foil, characterized by comprising, from inside to outside, a base layer, a buffer layer, an anti-oxidation layer and a protective layer; the base layer is high-purity electrolytic copper with a purity of not less than 99.99% and a thickness of 10μm; the buffer layer is a nickel-phosphorus alloy coated by a nitrogen-doped graphene@carbon nanotube core-shell structure, with a thickness of 0.5μm; the anti-oxidation functional layer is a nano-sized copper oxide@zeolite imidazolate framework material-8 core-shell structure, with the average particle size of the nano-sized copper oxide particles being 5-50nm; and the protective layer is a p-xylene film, with a thickness of 0.1μm.

[0068] The electrolyte comprises: 220g / L copper sulfate and 80g / L sulfuric acid, the electrolysis temperature is 60℃, and the current density is 40A / dm 2 .

[0069] The binder is polyimide.

[0070] The base layer preparation method comprises the following steps: placing a copper sulfate electrolyte into an electrolytic cell, using a titanium roller as a cathode and a lead-silver alloy as an anode placed in the electrolyte, and depositing the copper foil on the surface of the cathode titanium roller under the action of a direct current electric field.

[0071] The preparation method of the buffer layer comprises the following steps:

[0072] A1, nickel powder with a purity of ≥99.9% and red phosphorus powder with a purity of ≥99.5% are weighed according to a ratio of 95% nickel content and 5% phosphorus content, a vacuum induction melting furnace is used, the raw materials are placed into a magnesia crucible, vacuum is extracted to 10 -3Pa below, fill in high-purity argon protection, heating to 1600 DEG C at a rate of 15 DEG C / min, keep 30 min, through the bottom of the melt alloy liquid flow into the high-pressure nitrogen atomization device, nitrogen pressure is set to 10 MPa, the alloy liquid atomization into small particles, after cooling to collect the nickel-phosphorus alloy powder, using air classifier on the alloy powder screening, collect the particle size in 1-10 mu m range of particles, get the nickel-phosphorus alloy powder;

[0073] A2, the nickel-phosphorus alloy powder is put into a chemical vapor deposition reaction furnace, heated to 1200 DEG C under argon atmosphere, hydrogen is introduced, the flow rate is 50 sccm, and it is kept for 60 min. Then, a mixed gas of methane and hydrogen is introduced, the flow rate of methane is 20 sccm, the flow rate of hydrogen is 50 sccm, and it is kept for 20 min. Then, the methane is closed, and the temperature is lowered to room temperature under hydrogen atmosphere to obtain graphene-coated nickel-phosphorus alloy powder.

[0074] A3, the graphene-coated nickel-phosphorus alloy powder is put into a chemical vapor deposition reaction furnace again, heated to 850 DEG C under argon atmosphere, 0.1 g / mL ferrocene / dimethylbenzene solution is introduced into the reaction furnace through argon, the flow rate is 100 sccm, and it is kept for 60 min. Then, the ferrocene solution is closed, and the temperature is lowered to room temperature under argon atmosphere to obtain graphene@carbon nanotube core-shell structure-coated nickel-phosphorus alloy powder.

[0075] A4, the graphene@carbon nanotube core-shell structure-coated nickel-phosphorus alloy powder is mixed with a binder uniformly, and a heat pressing process is adopted to press the mixture into a buffer layer film under the conditions of a temperature of 400 DEG C and a pressure of 10 MPa. Then, the buffer layer film is attached to the surface of the base copper foil, the binder is made to play a role through heating and curing, and firm combination of the buffer layer and the base layer is realized.

[0076] A5, the above sample is put into a tube furnace, heated to 1000 DEG C under argon atmosphere, a mixed gas of ammonia and argon is introduced, the flow rate of ammonia is 50 sccm, the flow rate of argon is 100 sccm, and it is kept for 60 min. Then, the ammonia is closed, and the temperature is lowered to room temperature under argon atmosphere to obtain a nitrogen-doped graphene@carbon nanotube core-shell structure-coated nickel-phosphorus alloy buffer layer.

[0077] The preparation method of the oxidation-resistant layer comprises the following steps:

[0078] B1, copper nitrate is dissolved in ethylene glycol methyl ether to form a solution with a concentration of 0.3 mol / L, then citric acid is added as a complexing agent, and stirred uniformly. At 80 DEG C, ammonia water is slowly added dropwise to adjust the pH value of the solution to 8, and the stirring is continued for 30 min to form a stable sol. The sol is dried at 100 DEG C to obtain a dry gel, and the dry gel is calcined at 600 DEG C for 4 h to obtain nano-sized copper oxide particles.

[0079] B2, disperse the nano copper oxide particles in ethanol, add 5% of the mass of the nano copper oxide of 3-aminopropyl triethoxysilane, react for 3 h at 70°C under nitrogen atmosphere, centrifuge, wash with ethanol, and dry at 80°C under vacuum for 8 h;

[0080] B3, disperse the surface-treated nano copper oxide in methanol, add 30% of the mass of the nano copper oxide of zinc nitrate and 60% of 2-methylimidazole, stir and react for 24 h at room temperature, then mix with polyetheramine D230 at a mass ratio of 7:1, add toluene to form a solution with a solid content of 10%, treat under the conditions of high-speed stirring at 2000 r / min and ultrasonic at 350 W for 30 min, to obtain an antioxidant functional layer precursor solution;

[0081] B4, immerse the copper foil plated with the buffer layer into the antioxidant functional layer precursor solution, uniformly coat the precursor solution on the surface of the buffer layer by dip coating, and then dry at 120°C to form an antioxidant layer with uniform thickness.

[0082] The preparation method of the protective layer comprises the following steps:

[0083] Put the copper foil treated with the antioxidant layer into a vacuum deposition device, put p-xylylene dimer into a crucible of a sublimation furnace, the loading amount is not more than 2 / 3 of the volume of the crucible, heat to 200°C, and keep warm for 30 min, then transport the sublimated gas to a cracking furnace through nitrogen, then introduce it into a deposition chamber at 750°C for 3 min, and then deposit for 30 min at a deposition temperature of 60°C, to deposit and polymerize a p-xylylene film on the surface of the copper foil treated with the antioxidant layer.

[0084] Comparative Example 1: no coated nickel-phosphorus alloy as a buffer layer, and the rest of the processes are the same as in Example 1.

[0085] Comparative Example 2: no coated nano copper oxide as an antioxidant layer, and the rest of the processes are the same as in Example 1.

[0086] Comparative Example 3: epoxy resin directly as a protective layer, and the rest of the processes are the same as in Example 1.

[0087] Test Example:

[0088] 1. Antioxidant performance: 1000 h in an air atmosphere at 150°C, test the oxidation weight gain, and the results are shown in Table 1;

[0089] 2. Heat resistance and hydrothermal resistance: thermal cycle stability: 1000 cycles at -40°C to 125°C, test the resistance change rate; hydrothermal resistance: 85°C / 85% RH for 1000 h, observe the surface changes, and the results are shown in Table 2;

[0090] 3. High frequency dielectric properties: The dielectric constant ε and dielectric loss tangent tan δ were measured at a test frequency of 10 GHz, and the results are shown in Table 3.

[0091] Table 1 Results of antioxidation performance

[0092] Group Oxidative weight gain (mg / cm 2 ) Example 1 0.11 Example 2 0.12 Example 3 0.12 Comparative Example 1 0.14 Comparative Example 2 0.85 Comparative Example 3 0.12

[0093] Table 2 Results of heat resistance and hydro-heat resistance performance tests

[0094]

[0095]

[0096] Table 3 Results of high frequency dielectric property tests

[0097] Group Dielectric constant (ε) Dielectric loss tangent (tan δ) Example 1 2.62 ≤0.002 Example 2 2.64 ≤0.002 Example 3 2.64 ≤0.002 Comparative Example 1 3.5 ≥0.025 Comparative Example 2 3.6 ≥0.025 Comparative Example 3 3.8 ≥0.025

[0098] As shown in the above table, the multilayer composite copper oxide foil of Examples 1-3 can effectively improve the antioxidation and heat resistance and hydro-heat resistance performance, and effectively reduce the dielectric loss.

[0099] Although embodiments of the present application have been shown and described, it is to be understood that various modifications, substitutions, replacements and changes can be made to these embodiments without departing from the principles and spirit of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A multilayer composite antioxidant copper foil, characterized in that, From the inside out, it comprises a base layer, a buffer layer, an antioxidant layer, and a protective layer. The base layer is high-purity electrolytic copper with a purity of not less than 99.99% and a thickness of 10–50 μm. The buffer layer is a nickel-phosphorus alloy coated with a nitrogen-doped graphene@carbon nanotube core-shell structure and a thickness of 0.5–2 μm. The antioxidant functional layer is a nano-sized copper oxide@zeolite imidazole ester framework material-8 core-shell structure with an average particle size of 5–50 nm. The protective layer is a parylene film with a thickness of 0.1–0.5 μm.

2. The multilayer composite antioxidant copper foil according to claim 1, characterized in that, The base layer preparation method includes the following steps: placing copper sulfate electrolyte in an electrolytic cell, using a titanium roller as the cathode and a lead-silver alloy as the anode, and placing it in the electrolyte. Under the action of a DC electric field, copper foil is deposited on the surface of the cathode titanium roller to form a copper foil.

3. The multilayer composite antioxidant copper foil according to claim 2, characterized in that, The electrolyte consists of 180–220 g / L copper sulfate and 50–80 g / L sulfuric acid; the electrolysis temperature is 50–60 °C; and the current density is 20–40 A / dm³. 2 .

4. The multilayer composite antioxidant copper foil according to claim 1, characterized in that, The method for preparing the buffer layer includes the following steps: A1. Weigh nickel powder with a purity ≥99.9% and red phosphorus powder with a purity ≥99.5% at a ratio of 85-95% nickel content and 5-15% phosphorus content. Using a vacuum induction melting furnace, place the raw materials into a magnesium oxide crucible and evacuate to 10°C. -3 Below Pa, high-purity argon gas is introduced for protection, and the temperature is heated to 1500-1600℃ at a heating rate of 10-15℃ / min, and held for 20-30min. The molten alloy liquid is then fed into a high-pressure nitrogen atomization device through a bottom nozzle. The nitrogen pressure is set to 5-10MPa to atomize the alloy liquid into fine particles. After cooling, the nickel-phosphorus alloy powder is collected. The alloy powder is then sieved using an air classifier to collect particles with a particle size in the range of 1-10μm to obtain nickel-phosphorus alloy powder. A2. Place the nickel-phosphorus alloy powder into a chemical vapor deposition reactor and heat it to 1000-1200℃ under an argon atmosphere. Then, introduce hydrogen gas at a flow rate of 30-50 sccm and maintain the temperature for 30-60 min. Next, introduce a mixture of methane and hydrogen gas at a flow rate of 10-20 sccm and a flow rate of 30-50 sccm and maintain the temperature for 10-20 min. Then, turn off the methane gas and cool it to room temperature under a hydrogen atmosphere to obtain graphene-coated nickel-phosphorus alloy powder. A3. The graphene-coated nickel-phosphorus alloy powder is placed back into a chemical vapor deposition reactor and heated to 750-850°C under an argon atmosphere. A 0.05-0.1 g / mL ferrocene / xylene solution is introduced into the reactor through argon gas at a flow rate of 80-100 sccm and maintained for 30-60 min. The ferrocene solution is then turned off, and the temperature is lowered to room temperature under an argon atmosphere to obtain graphene@carbon nanotube core-shell structure-coated nickel-phosphorus alloy powder. A4. The nickel-phosphorus alloy powder coated with graphene@carbon nanotube core-shell structure is mixed evenly with the binder. The mixture is pressed into a buffer layer film with a thickness of 0.5-2μm using a hot pressing process at a temperature of 300-400℃ and a pressure of 5-10MPa. The film is then bonded to the surface of the base copper foil. The binder is cured by heating to achieve a strong bond between the buffer layer and the base layer. A5. Place the above sample in a tube furnace and heat it to 800-1000℃ in an argon atmosphere. Then, introduce a mixture of ammonia and argon gas at a flow rate of 30-50 sccm and an argon flow rate of 80-100 sccm. Maintain this temperature for 30-60 minutes, then turn off the ammonia gas and cool it to room temperature in an argon atmosphere to obtain a nickel-phosphorus alloy buffer layer coated with a nitrogen-doped graphene@carbon nanotube core-shell structure.

5. The multilayer composite antioxidant copper foil according to claim 4, characterized in that, The adhesive is one of epoxy resin, phenolic resin, or polyimide.

6. The multilayer composite antioxidant copper foil according to claim 1, characterized in that, The method for preparing the antioxidant layer includes the following steps: B1. Dissolve copper nitrate in ethylene glycol methyl ether to form a solution with a concentration of 0.1-0.3 mol / L. Then add citric acid as a complexing agent and stir until homogeneous. At 60-80℃, slowly add ammonia water to adjust the pH of the solution to 7-8. Continue stirring for 10-30 min to form a stable sol. Dry the sol at 80-100℃ to obtain a dry gel. Then calcine the dry gel at 400-600℃ for 2-4 h to obtain nano-sized copper oxide particles. B2. Disperse the nano-copper oxide particles in ethanol, add 3-5% by weight of 3-aminopropyltriethoxysilane, react at 50-70℃ for 1-3 hours under nitrogen atmosphere, centrifuge, wash with ethanol, and vacuum dry at 60-80℃ for 4-8 hours. B3. Disperse the surface-treated nano-copper oxide in methanol, add 20-30% zinc nitrate and 50-60% 2-methylimidazole by mass of nano-copper oxide, stir and react at room temperature for 12-24 h, then mix with polyetheramine D230 at a mass ratio of 5-7:1, add toluene to form a solution with a solid content of 10%, and treat under high-speed stirring at 1000-2000 r / min and ultrasonic conditions of 200-350 W for 10-30 min to obtain the antioxidant functional layer precursor solution; B4. Immerse the copper foil with the buffer layer into the antioxidant functional layer precursor solution, and use the dip coating method to uniformly coat the precursor solution on the surface of the buffer layer. Then dry it at 80-120℃ to form an antioxidant layer of uniform thickness.

7. The multilayer composite antioxidant copper foil according to claim 1, characterized in that, The method for preparing the protective layer includes the following steps: Copper foil treated with an antioxidant layer is placed in a vacuum deposition apparatus. Para-xylene dimer is placed in a crucible of a sublimation furnace, with the loading amount not exceeding 2 / 3 of the crucible volume. The mixture is heated to 150–200°C and held for 10–30 minutes. The sublimated gas is then transported to a pyrolysis furnace via nitrogen. The mixture is then held at 650–750°C for 1–3 minutes and then introduced into the deposition chamber. The deposition time is 10–30 minutes, and the deposition temperature is 40–60°C. This process deposits and polymerizes the para-xylene film on the surface of the copper foil treated with the antioxidant layer.

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