Copper-based surface metal nanostructure preparation method based on ultrasonic oscillation

Abstract

The invention discloses a preparation method of a copper-based surface metal nanostructure based on ultrasonic oscillation, which comprises the following specific steps: S1, pretreatment of a base material: cleaning and drying an oxygen-free copper base material to ensure that the surface is free of oil stain, dust and other pollutants; s2, preparing a precursor solution, selecting corresponding metal salt, a reducing agent and a dispersing agent according to the type of the metal nanostructure, and dissolving in an ethylene glycol solvent to form the precursor solution; s3, an ultrasonic oscillation reaction is conducted, specifically, the pretreated oxygen-free copper is immersed in the precursor solution, oscillation is conducted through an ultrasonic oscillation device, and metal ions are evenly deposited on the surface of the oxygen-free copper; and S4, post-treatment is conducted, specifically, the sample is taken out, cleaned and dried, and the oxygen-free copper substrate with the uniform metal nanostructure on the surface is obtained.The method solves the problem of compatibility of the multi-metal nanostructure and has the advantages of being compact in process, low in energy consumption and high in structural uniformity.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of metal material engineering, and particularly relates to a copper-based surface metal nanostructure preparation method based on ultrasonic oscillation. BACKGROUND

[0002] With the rapid development of the microelectronics industry, the sintering technology of chips puts forward higher requirements for the nanocrystalline structure of the material surface. The nanocrystalline structure can significantly improve the activity, specific surface area and sintering performance of the material, thereby improving the reliability and efficiency of chip connection.

[0003] At present, the traditional copper surface nanostructure preparation methods mainly include photolithography, chemical etching and electrochemical deposition. However, the photolithography depends on expensive photolithography machines and mask plates, and the process is complex and difficult to prepare in a large area; the chemical etching needs to use strong acid or strong base, which will produce waste liquid containing heavy metal ions, and the environmental protection risk is high, in addition, the reaction rate of the chemical etching is difficult to accurately control, which is easy to cause excessive corrosion or uneven structure; the electrochemical deposition needs to preinstall a template on a conductive substrate, which usually needs 5-7 processes, and the process steps are complicated; in addition, the deposition layer prepared by the electrochemical deposition method has weak bonding force with the copper substrate, and is easy to peel off under mechanical stress. SUMMARY

[0004] The purpose of the application is to solve the problems in the prior art, and provide a method for efficiently and controllably preparing various metal nanostructures on the surface of oxygen-free copper.

[0005] The copper-based surface metal nanostructure preparation method based on ultrasonic oscillation comprises the following specific steps: S1: substrate pretreatment, cleaning and drying the oxygen-free copper substrate to ensure that the surface is free of oil stains, dust and other pollutants; S2: configure a precursor solution, select corresponding metal salt, reducing agent and dispersing agent according to the type of metal nanostructure, dissolve in ethylene glycol solvent to form a precursor solution, and the concentration of the precursor solution is adjusted according to the thickness and density of the required nanostructure; S3: ultrasonic oscillation reaction, immerse the pretreated oxygen-free copper in the precursor solution, use an ultrasonic oscillation device to oscillate, make the metal ions uniformly deposit on the surface of the oxygen-free copper, react for 30-90 minutes under the conditions of ultrasonic frequency of 20-80 kHz, power of 300-800 W and temperature of 50-90℃, and drive the metal ions to reduce and grow into nanostructures by cavitation effect; S4: post-treatment: take out the sample, clean and dry to obtain an oxygen-free copper substrate with uniform metal nanostructure on the surface.

[0006] The further improvement of the present application is that the metal nanostructure is one of Ag nanostructure, Au nanostructure or Cu nanostructure, and the particle size ranges from 50 to 200 nm.

[0007] The further improvement of the present application is that when the Ag nanostructure is prepared, the precursor solution in the step S2 comprises the following components: silver nitrate (AgNO3) with a concentration of 0.05-0.2 mol / L; ascorbic acid (C6H8O6) with a concentration of 0.1-0.4 mol / L; the dispersing agent is polyvinylpyrrolidone (PVP) with an addition amount of 0.3-1.0 g / L; and the ultrasonic parameters are frequency of 30-50 kHz, power of 400-600 W and reaction temperature of 55-70℃.

[0008] The further improvement of the present application is that when the Au nanostructure is prepared, the precursor solution in the step S2 comprises the following components: chloroauric acid (HAuCl4) with a concentration of 0.02-0.1 mol / L; sodium citrate (Na3C6H5O7) with a concentration of 0.05-0.2 mol / L; the morphology directing agent is cetyltrimethylammonium bromide (CTAB) with an addition amount of 0.5-2.0 g / L; and the ultrasonic parameters are frequency of 50-70 kHz, power of 500-700 W and reaction temperature of 70-90℃.

[0009] The further improvement of the present application is that when the Cu nanostructure is prepared, the precursor solution in the step S2 comprises the following components: copper sulfate (CuSO4) with a concentration of 0.1-0.3 mol / L; the composite reducing agent is a mixture of sodium hypophosphite (NaH2PO2) and ascorbic acid with a total concentration of 0.1-0.5 mol / L; the dispersing agent is PVP with an addition amount of 0.1-0.5 g / L; and the ultrasonic parameters are frequency of 25-45 kHz, power of 300-500 W and reaction temperature of 60-80℃.

[0010] The further improvement of the present application is that in the step S1, the oxygen-free copper matrix is subjected to vacuum annealing treatment, the annealing temperature is 500-650℃, the vacuum degree is ≤10⁻³ Pa, and the temperature is kept for 1-3 hours and then cooled to room temperature under the protection of inert gas.

[0011] The further improvement of the present application is that in the step S1, the oxygen-free copper sheet is immersed in 15% H2O2, 5% H2SO4 and deionized water for cleaning for 5 minutes to remove surface oxides and impurities, then washed with deionized water and dried by nitrogen blowing.

[0012] The further improvement of the present application is that in the step S1, the oxygen-free copper matrix comprises the following components: Cu≥99.99% and O≤5 ppm by weight.

[0013] Compared with the prior art, the copper-based surface metal nanostructure preparation method based on ultrasonic oscillation at least achieves the following beneficial effects: The copper-based surface metal nanostructure preparation method based on ultrasonic oscillation solves the compatibility problem of multi-metal nanostructures, has the advantages of compact process, low energy consumption, and high structural uniformity; the ultrasonic oscillation technology can efficiently realize directional regulation of the metal surface nanostructure due to its cavitation effect and local high-pressure characteristics; by designing an ultrasonic solution system containing oxidation-etching dual-functional components, combining the synergistic mechanism of cavitation effect and chemical reaction, and realizing low-cost and high-uniformity controlled growth of the metal nano-junction layer structure on the copper surface, the performance is greatly improved; by adjusting the solution composition, the controlled preparation of Ag, Au and Cu nanostructures is realized, and the synergistic effect of ultrasonic parameters and solution chemistry can regulate the size and distribution density of the nano-particles, which can meet the application requirements of chip sintering. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 The flowchart of the present application. DETAILED DESCRIPTION

[0015] Various exemplary embodiments of the present application will now be described in detail. It should be noted that the relative arrangement of components and steps, numerical expressions, and numerical values set forth in these embodiments are not limiting to the scope of the present application unless otherwise specifically stated. The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way limiting to the present application and its applications or uses.

[0016] Techniques, methods, and equipment known to those of ordinary skill in the relevant art can not be discussed in detail, but should be considered part of the specification where appropriate. In all examples shown and discussed herein, any specific value should be interpreted as merely illustrative, not as a limitation. Therefore, other examples of exemplary embodiments can have different values.

[0017] Reference Figure 1 The copper-based surface metal nanostructure preparation method based on ultrasonic oscillation is characterized by the following specific steps: S1: substrate pretreatment, cleaning and drying the oxygen-free copper substrate to ensure that the surface is free of oil stains, dust and other contaminants; S2: configure a precursor solution, select corresponding metal salts, reducing agents and dispersants according to the type of metal nanostructure, dissolve in ethylene glycol solvent to form a precursor solution, and adjust the concentration of the precursor solution according to the thickness and density of the required nanostructure; S3: ultrasonic oscillation reaction, the pretreated oxygen-free copper is immersed in the precursor solution, and ultrasonic oscillation device is used for oscillation, so that metal ions are uniformly deposited on the surface of the oxygen-free copper, and under the conditions of ultrasonic frequency of 20-80 kHz, power of 300-800 W, and temperature of 50-90 DEG C, reaction for 30-90 minutes, the metal ions are driven to reduce and grow into nano structures by cavitation effect; S4: post-treatment: the sample is taken out, washed and dried to obtain an oxygen-free copper matrix with uniform metal nano structures on the surface.

[0018] The further improvement of the application is that the metal nano structure is one of Ag nano structure, Au nano structure or Cu nano structure, and the particle size range is 50-200 nm.

[0019] The further improvement of the application is that when the Ag nano structure is prepared, the precursor solution in the step S2 comprises the following components: silver nitrate (AgNO3) concentration of 0.05-0.2 mol / L; ascorbic acid (C6H8O6) concentration of 0.1-0.4 mol / L; dispersing agent is polyvinylpyrrolidone (PVP), and the addition amount is 0.3-1.0 g / L; the ultrasonic parameters are frequency of 30-50 kHz, power of 400-600 W, and reaction temperature of 55-70 DEG C.

[0020] The further improvement of the application is that when the Au nano structure is prepared, the precursor solution in the step S2 comprises the following components: chloroauric acid (HAuCl4) concentration of 0.02-0.1 mol / L; sodium citrate (Na3C6H5O7) concentration of 0.05-0.2 mol / L; morphology directing agent is cetyltrimethylammonium bromide (CTAB), and the addition amount is 0.5-2.0 g / L; the ultrasonic parameters are frequency of 50-70 kHz, power of 500-700 W, and reaction temperature of 70-90 DEG C.

[0021] The further improvement of the application is that when the Cu nano structure is prepared, the precursor solution in the step S2 comprises the following components: copper sulfate (CuSO4) concentration of 0.1-0.3 mol / L; the composite reducing agent is a mixture of sodium hypophosphite (NaH2PO2) and ascorbic acid, and the total concentration is 0.1-0.5 mol / L; the dispersing agent is PVP, and the addition amount is 0.1-0.5 g / L; the ultrasonic parameters are frequency of 25-45 kHz, power of 300-500 W, and reaction temperature of 60-80 DEG C.

[0022] The further improvement of the application is that in the step S1, the oxygen-free copper matrix is subjected to vacuum annealing treatment, the annealing temperature is 500-650 DEG C, the vacuum degree is ≤10⁻³ Pa, the temperature is kept for 1-3 hours, and then cooled to room temperature under the protection of inert gas.

[0023] Further improvement of the present application is that in step S1, the oxygen-free copper sheet is immersed in 15% H2O2, 5% H2SO4, deionized water for 5 minutes to remove surface oxides and impurities, then washed with deionized water and dried with nitrogen.

[0024] Further improvement of the present application is that in step S1, the oxygen-free copper substrate component is: Cu≥99.99%, O≤5ppm by weight.

[0025] Example 1: Preparation of Ag nanostructure on the surface of oxygen-free copper (1) Substrate pretreatment: Select oxygen-free copper plate (Cu≥99.99%, O≤5ppm); Vacuum annealing: place the sample in a vacuum furnace (10⁻³ Pa), heat to 600°C for 2 hours, then introduce argon to cool to room temperature, eliminate surface stress and residual oxides.

[0026] (2) Preparation of precursor solution Dissolve 0.1 mol / L silver nitrate (AgNO3) in ethylene glycol (EG), add 0.5 g / L polyvinylpyrrolidone (PVP) as a dispersant; 0.2 mol / L ascorbic acid (C6H8O6) as a reducing agent, dissolved in ethylene glycol (EG).

[0027] (3) Ultrasonic oscillation reaction Immerse the pretreated oxygen-free copper into the dispersant and place it in an ultrasonic reaction tank (frequency 40 kHz, power 500 W) with water bath temperature control at 60°C. Add the reducing agent drop by drop and ultrasonically treat for 30 minutes. Ultrasonic cavitation effect promotes the rapid reduction of Ag⁺ to nanoparticles, while PVP inhibits particle agglomeration, forming uniform Ag nanostructures (particle size 50-100 nm).

[0028] (4) Post-processing Take out the sample, wash it with deionized water and ethanol alternately, and dry it with nitrogen to obtain an oxygen-free copper substrate with uniform metal nanostructures on the surface.

[0029] Example 2: Preparation of Au nanostructure on the surface of oxygen-free copper (1) Substrate pretreatment Pretreatment: immerse the oxygen-free copper sheet in 15% H2O2, 5% H2SO4, deionized water for 5 minutes to remove surface oxides and impurities, then wash with deionized water and dry with nitrogen.

[0030] (2) Preparation of precursor solution 0.05 mol / L chloroauric acid (HAuCl4) was dissolved in EG, and 1 g / L hexadecyltrimethylammonium bromide (CTAB) was added as a morphology directing agent; 0.1 mol / L sodium citrate (Na3C6H5O7) was used as a reducing agent.

[0031] (3) Ultrasonic oscillation response Oxygen-free copper was immersed in a morphology guiding agent, and the ultrasonic tank parameters were adjusted to 60kHz, 600W, and 80℃. A reducing agent was slowly added, followed by ultrasonic treatment for 45 minutes. CTAB guided the directional growth of Au nanoparticles into a dendritic structure, thereby enhancing the specific surface area.

[0032] (4) Post-processing The sample was removed and cleaned alternately with deionized water and ethanol, and then dried with nitrogen to obtain an oxygen-free copper substrate with a uniform metallic nanostructure on the surface.

[0033] Example 3: Preparation of Cu nanostructures on oxygen-free copper surface (1) Substrate pretreatment Oxygen-free copper plates (Cu≥99.99%, O≤5ppm) are selected. Vacuum annealing: The sample is placed in a vacuum furnace (10⁻³Pa), heated to 600℃ and held for 2 hours, and then cooled to room temperature by purging with argon gas to eliminate surface stress and residual oxides.

[0034] (2) Preparation of precursor solution 0.2 mol / L copper sulfate (CuSO4) was dissolved in ethylene glycol (EG), and 0.3 g / L PVP and 0.1 g / L sodium hypophosphite (NaH2PO2) were added to form a composite reducing solution.

[0035] (3) Ultrasonic oscillation response Oxygen-free copper was immersed in a composite reducing solution, and the ultrasonic parameters were set to 35kHz, 400W, and 70℃.

[0036] After continuous sonication for 60 minutes, sodium hypophosphite releases active hydrogen atoms under ultrasonic drive, reducing Cu² to nanoparticles, while EG solvent inhibits oxidation.

[0037] (4) Post-processing The sample was removed and cleaned alternately with deionized water and ethanol, and then dried with nitrogen to obtain an oxygen-free copper substrate with a uniform metallic nanostructure on the surface.

Claims

1. A method for preparing copper-based surface metal nanostructures based on ultrasonic oscillation, characterized in that, The specific steps include: S1: Substrate pretreatment, the oxygen-free copper substrate is cleaned and dried to ensure that the surface is free of oil, dust and other contaminants; S2: Prepare a precursor solution by selecting the corresponding metal salt, reducing agent and dispersant according to the type of metal nanostructure, and dissolving them in ethylene glycol solvent to form a precursor solution. The concentration of the precursor solution is adjusted according to the thickness and density of the required nanostructure. S3: Ultrasonic oscillation reaction. Pretreated oxygen-free copper is immersed in a precursor solution and oscillated using an ultrasonic oscillation device to uniformly deposit metal ions on the surface of oxygen-free copper. The reaction is carried out for 30 to 90 minutes under ultrasonic frequency of 20 to 80 kHz, power of 300 to 800 W, and temperature of 50 to 90 °C. The metal ions are reduced and directionally grown into nanostructures through cavitation effect. S4: Post-processing: Remove the sample, clean and dry it to obtain an oxygen-free copper substrate with a uniform metal nanostructure on the surface.

2. The method for preparing copper-based surface metal nanostructures based on ultrasonic oscillation according to claim 1, characterized in that, The metal nanostructure is one of Ag nanostructure, Au nanostructure or Cu nanostructure, with a particle size range of 50 to 200 nm.

3. The method for preparing copper-based surface metal nanostructures based on ultrasonic oscillation according to claim 2, characterized in that, When preparing Ag nanostructures, the precursor solution in step S2 includes the following components: silver nitrate (AgNO3) concentration of 0.05–0.2 mol / L; ascorbic acid (C6H8O6) concentration of 0.1–0.4 mol / L; dispersant is polyvinylpyrrolidone (PVP) added at an amount of 0.3–1.0 g / L; ultrasonic parameters are frequency of 30–50 kHz, power of 400–600 W, and reaction temperature of 55–70 °C.

4. The method for preparing copper-based surface metal nanostructures based on ultrasonic oscillation according to claim 2, characterized in that, When preparing Au nanostructures, the precursor solution in step S2 includes the following components: chloroauric acid (HAuCl4) at a concentration of 0.02–0.1 mol / L; sodium citrate (Na3C6H5O7) at a concentration of 0.05–0.2 mol / L; a morphology directing agent of hexadecyltrimethylammonium bromide (CTAB) at an addition amount of 0.5–2.0 g / L; and ultrasonic parameters of a frequency of 50–70 kHz, a power of 500–700 W, and a reaction temperature of 70–90 °C.

5. The method for preparing copper-based surface metal nanostructures based on ultrasonic oscillation according to claim 2, characterized in that, When preparing Cu nanostructures, the precursor solution in step S2 includes the following components: copper sulfate (CuSO4) concentration of 0.1–0.3 mol / L; a composite reducing agent of sodium hypophosphite (NaH2PO2) and ascorbic acid with a total concentration of 0.1–0.5 mol / L; a dispersant of PVP with an addition amount of 0.1–0.5 g / L; and ultrasonic parameters of frequency 25–45 kHz, power 300–500 W, and reaction temperature 60–80 °C.

6. The method for preparing copper-based surface metal nanostructures based on ultrasonic oscillation according to claim 1, characterized in that, In step S1, the oxygen-free copper substrate is subjected to vacuum annealing at a temperature of 500–650°C and a vacuum degree of ≤10⁻³ Pa. After holding at this temperature for 1–3 hours, it is cooled to room temperature under inert gas protection.

7. The method for preparing copper-based surface metal nanostructures based on ultrasonic oscillation according to claim 1, characterized in that, In step S1, the oxygen-free copper sheet is immersed in 15% H2O2, 5% H2SO4 and deionized water for 5 minutes to remove surface oxides and impurities, then rinsed with deionized water and dried with nitrogen.

8. The method for preparing copper-based surface metal nanostructures based on ultrasonic oscillation according to claim 1, characterized in that, In step S1, the composition of the oxygen-free copper substrate is: Cu≥99.99% and O≤5ppm by weight.

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