A method for producing a metal film by an electrochemical deposition method

Abstract

The application discloses a metal film preparation method by electrochemical deposition, and relates to the technical field of metal film preparation, and comprises the following steps: raw material pretreatment, pretreatment of the surface of a substrate, pretreatment of an anode, and preparation of an electrolyte, addition of an efficient dispersing agent in the electrolyte, precise deposition of a film layer, precise deposition of the pretreated substrate by electrochemical deposition, drying and solidification, removal of residual electrolyte on the surface of the substrate after deposition, placement of the substrate into a numerical control drying oven, setting of a drying temperature of 110 DEG C, setting of a temperature rising rate of 10 DEG C / min, and setting of a drying time of 2h, and environmental protection post-treatment, cleaning, detection, recovery of waste raw materials, and packaging of the prepared substrate. The application realizes efficient, energy-saving, low-cost, and environmentally-friendly metal film preparation by optimizing a raw material formula, improving a preparation device, perfecting process parameters, and connecting a process.

Description

Technical Field

[0001] This invention belongs to the field of metal film preparation technology, and specifically relates to a method for preparing metal films by electrochemical deposition. Background Technology

[0002] Metal membranes are functional materials with a porous structure, high mechanical strength, excellent electrical and thermal conductivity, and corrosion resistance, based on metal or alloy. Their core advantage lies in balancing filtration and separation performance with structural stability, and they can replace traditional organic membranes and ceramic membranes in complex working conditions such as high temperature, high pressure, and strong corrosion.

[0003] Current status and development of existing processes: With the upgrading of demand for functional materials, metal film preparation is gradually developing towards "thinning, high precision, low energy consumption, and large-scale production". At present, the mainstream industrial products have a thickness range of 0.1~10μm and a pore size that can be controlled between 0.05~5μm. The materials are mainly stainless steel (304, 316L), copper, titanium and nickel-based alloys. The preparation technology has been upgraded from traditional intermittent deposition to continuous deposition, and the equipment has been optimized from manual operation to semi-automatic operation. The film performance and production efficiency have been improved to a certain extent, but the technical bottleneck of high energy consumption and low yield has not yet been broken.

[0004] Currently, the mainstream methods for preparing metal films mainly include magnetron sputtering, electrochemical deposition, powder metallurgy, and vacuum evaporation. The shortcomings of existing electrochemical deposition processes are as follows: 1. Low yield and poor quality stability: In electrochemical deposition, uneven electrolyte concentration distribution and current density fluctuations lead to a porosity deviation of over 20% and unstable conductivity in the film layer; 2. High energy consumption and long production cycle: Energy consumption per unit product is as high as 180~220 kWh / ton; at the same time, the existing process has poor connections between substrate pretreatment, film deposition, sintering, and other steps, resulting in an overall production cycle of 1~2 days and low production efficiency; 3. High production cost: On the one hand, high energy consumption leads to energy costs accounting for 40%~50% of production costs; on the other hand, electrochemical deposition requires the use of high-purity electrolyte raw materials, resulting in high raw material costs; in addition, the current process has a low yield (only about 72%) and a raw material loss rate of over 20%, further increasing production costs; 4. Film performance needs improvement: The conductivity of copper conductive films prepared by the existing process is low (only about 85% of that of pure copper), which cannot meet the requirements of high-end electronic devices; 5. Complex operation and poor environmental performance: Existing processes require the use of toxic and harmful reagents such as acetone and hydrofluoric acid for substrate pretreatment, which easily causes environmental pollution and endangers the health of operators; parameters in film deposition and sintering processes need to be manually adjusted, which is difficult to operate and human error can easily lead to fluctuations in product quality; the waste electrolyte generated by electrochemical deposition is not recycled and directly discharged, causing water pollution. Based on the shortcomings of existing technologies, we designed and proposed a metal film preparation method using electrochemical deposition. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies, such as low yield, poor quality stability, high energy consumption, long production cycle, high production cost, need for improved film performance, complex operation, and poor environmental friendliness. This invention proposes an electrochemical deposition method for preparing metal films. This electrochemical deposition method achieves efficient, energy-saving, low-cost, and environmentally friendly metal film preparation by optimizing raw material formulations, improving preparation equipment, and perfecting process parameters and connections.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: Design a method for preparing metal films by electrochemical deposition, comprising the following steps: Step 1, Raw material pretreatment: Pretreatment of the substrate surface, pretreatment of the anode and preparation of electrolyte for later use; Step 2, Precise Film Deposition: Precise film deposition is performed on the pretreated substrate using electrochemical deposition. The precise film deposition using electrochemical deposition includes the following steps: Step 21: Use the pretreated substrate as the cathode and install it on the cathode holder of the electrochemical deposition instrument. Adjust the distance between the cathode and the anode to make the two electrodes parallel. Step 22: Inject the prepared electrolyte into the sedimentation tank and start the electrolyte circulation device to make the electrolyte concentration distribution uniform. Step 23: Start the electrochemical deposition apparatus, set the current density to 20 mA / cm², the deposition temperature to 35°C, and the deposition time to 45 min. At the same time, continuously stir the electrolyte. Step 3, Drying and curing: After deposition, remove the substrate, remove the residual electrolyte on the surface, put it into a CNC oven, set the drying temperature to 110℃, with a heating rate of 10℃ / min, and a drying time of 2 hours; Step 4, Environmental post-processing: cleaning, testing, waste material recycling and packaging of the substrate prepared in step 3.

[0007] Furthermore, in step 1, the substrate pretreatment includes: immersing the substrate in a 3% hydrofluoric acid solution for 8 minutes to remove the surface oxide layer, rinsing it three times with deionized water for 4 minutes each time, ultrasonically cleaning it in anhydrous ethanol for 10 minutes, removing it and drying it in a 105°C oven for 2 hours, and then cooling it to room temperature.

[0008] Furthermore, in step 1, the anode pretreatment includes: rinsing the pure copper sheet with deionized water, immersing it in anhydrous ethanol for ultrasonic cleaning for 5 minutes to remove surface oil, air-drying it naturally, and then installing it on the anode holder of the electrochemical deposition instrument.

[0009] Furthermore, in step 1, the electrolyte preparation includes: according to a preset ratio, copper sulfate, sulfuric acid, polyvinyl alcohol, sodium dodecylbenzenesulfonate, and silver nitrate are added sequentially to deionized water, placed in a constant temperature magnetic stirrer, stirred at a temperature of 40°C, a stirring speed of 400 r / min, and a stirring time of 1.5 h until completely dissolved, allowed to stand for 30 min, filtered through a 0.05 μm pore size filter membrane to remove impurities and undissolved particles, and poured into an electrolyte circulation device.

[0010] Furthermore, in step 21, the distance between the cathode and the anode is adjusted to 5 cm.

[0011] Furthermore, in step 22, the circulation rate of the electrolyte circulation device is 15 L / h.

[0012] Furthermore, in step 4, the cleaning includes: immersing the substrate of the semi-finished product in anhydrous ethanol for ultrasonic cleaning for 5 minutes to remove residual impurities on the surface, and then air-drying it naturally. Testing: Testing the substrate's conductivity, film thickness, film uniformity, and film adhesion; Waste material recycling and packaging: Substandard substrates with conductivity <98% pure copper, film thickness deviation >5%, and pinholes in the film layer are redeposited. Waste electrolyte is recycled through a circulation device and can be reused after replenishing raw materials. Qualified substrates are packaged with anti-static materials and stored in a dry, dust-free environment.

[0013] The present invention proposes an electrochemical deposition method for preparing metal films, which has the following advantages: (1) The present invention significantly improves the yield and optimizes the quality stability: by adding a high-efficiency dispersant, sodium dodecylbenzenesulfonate, to the electrolyte at a rate of 0.03~0.08 mol / L, and by using a circulating stirring device to make the electrolyte concentration distribution uniform, the membrane porosity deviation can be reduced to below 8%, the overall yield is increased from the existing 72% to over 95%, the raw material loss rate is reduced to below 5%, and the number of qualified products produced per batch is increased by 31.9%.

[0014] (2) The production efficiency of this invention is greatly improved: the process connection is optimized and a continuous production line is adopted to seamlessly connect the substrate pretreatment, film deposition, drying and post-treatment. The overall production cycle is shortened from 1-2 days to 8-10 hours, the production efficiency is increased by more than 60%, and the annual output of a single production line is increased from 8,000 tons to 13,000 tons. The fully automatic CNC equipment is adopted to realize the automatic control of parameters in each link, reduce manual intervention, and further improve the production efficiency by 25%.

[0015] (3) The membrane performance of the present invention is comprehensively improved and the service life is extended: the copper membrane electrolyte formula is optimized and trace amounts of silver ions (0.005~0.01mol / L) are added, and the conductivity is increased to more than 98% of that of pure copper, which meets the needs of high-end electronic devices; the membrane pore structure is optimized, so that the membrane flux of the porous metal membrane is increased to 85~110L / (mh), which is 41.7%~83.3% higher than the existing process. It can continuously and stably filter for 35 days without stopping for cleaning, and the anti-fouling ability is significantly improved.

[0016] (4) The present invention is easy to operate and has greatly improved environmental protection: It adopts fully automatic CNC equipment, and operators can be put to work after simple training. No professional technicians are required, the difficulty of operation is reduced by 70%, and the labor cost is reduced by 45%; it uses environmentally friendly cleaning agents to reduce the emission of waste gas and waste liquid; it realizes the recycling of waste electrolyte, realizes green production, and meets environmental protection requirements; it simplifies the process, optimizing the existing 4 core links into 3: integrated substrate pretreatment, precise film deposition-drying, and environmentally friendly post-treatment), reducing the process by 25%, making the operation process simpler and easier to promote on a large scale.

[0017] (5) The invention has wider applicability: The metal membrane prepared by the invention can be flexibly adjusted in terms of membrane thickness (0.1~10μm), pore size (0.05~5μm) and material (stainless steel, copper, titanium, nickel-based alloy) according to different application scenarios, and is suitable for multiple fields such as industrial wastewater filtration, electronic conductivity, biomedicine, new energy, and seawater desalination; single-layer and multi-layer composite metal membranes can be prepared to meet differentiated needs, such as multi-layer composite stainless steel membranes, which can achieve filtration and corrosion resistance at the same time, and are suitable for high-difficulty industrial wastewater treatment scenarios. Attached Figure Description

[0018] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 This is a flowchart illustrating the present invention. Detailed Implementation

[0019] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0020] The structural features of the present invention will now be described in detail with reference to the accompanying drawings.

[0021] This embodiment takes the preparation of copper metal film as an example.

[0022] Industrial-grade, conventional raw materials are used, including: (1) Substrate material: silicon wafer, thickness 0.3mm, size 80mm×80mm, surface free of scratches; (2) Electrode material: pure copper sheet, purity 99.5%, size 100mm×100mm×2mm, used as anode; (3) Electrolyte raw materials: industrial grade copper sulfate (CuSO4·5H2O) with a purity of 99%, sulfuric acid (H2SO4) with a concentration of 98%, deionized water, industrial grade polyvinyl alcohol (brightener), industrial grade sodium dodecylbenzenesulfonate (dispersant), and silver nitrate (AgNO3, conductive modifier) ​​with a purity of 99.8%.

[0023] (4) Pretreatment raw materials: environmentally friendly 3% hydrofluoric acid solution, anhydrous ethanol, and deionized water. Raw material ratio (electrolyte, volume 1L): copper sulfate 1.2mol / L, sulfuric acid 1.0mol / L, polyvinyl alcohol 0.03mol / L, sodium dodecylbenzenesulfonate 0.05mol / L, silver nitrate 0.008mol / L, and deionized water to 1L.

[0024] Industrial-grade standard equipment, readily available equipment includes: ultrasonic cleaner, constant temperature magnetic stirrer, fully automatic electrochemical deposition apparatus (current density adjustable from 0 to 50 mA / cm²), CNC drying oven, four-probe tester, film thickness tester, microscope (1000x magnification for observing film uniformity), electronic balance (accuracy 0.001g), and electrolyte circulation device.

[0025] See Figure 1 A method for preparing a metal film by electrochemical deposition includes the following steps: S1. Raw material pretreatment: Pretreatment of the substrate surface, pretreatment of the anode and preparation of electrolyte, addition of a high-efficiency dispersant to the electrolyte for later use.

[0026] ① Substrate pretreatment: Immerse the silicon wafer in a 3% hydrofluoric acid solution for 8 minutes to remove the surface oxide layer, rinse with deionized water 3 times for 4 minutes each time; ultrasonically clean in anhydrous ethanol for 10 minutes, remove and dry in a 105℃ oven for 2 hours, cool to room temperature and set aside.

[0027] ② Anode pretreatment: Rinse the pure copper sheet with deionized water, immerse it in anhydrous ethanol and ultrasonically clean it for 5 minutes to remove surface oil, let it air dry, and then install it on the anode seat of the electrochemical deposition instrument for later use. ③ Electrolyte preparation: According to the preset ratio, add copper sulfate, sulfuric acid, polyvinyl alcohol, sodium dodecylbenzenesulfonate and silver nitrate to deionized water in sequence, place in a constant temperature magnetic stirrer, stir at 40℃, stir at 400r / min, stir for 1.5h until completely dissolved; let stand for 30min, filter with a 0.05μm filter membrane to remove impurities and undissolved particles, pour into the electrolyte circulation device, and keep for later use.

[0028] S2. Precise Film Deposition: Precise film deposition is performed on the pretreated substrate using electrochemical deposition. The precise film deposition method using electrochemical deposition includes the following steps: S21. Use the pretreated silicon wafer as the cathode and install it on the cathode holder of the electrochemical deposition instrument. Adjust the distance between the cathode and the anode to 5cm to ensure that the two electrodes are parallel. S22. Inject the prepared electrolyte into the deposition tank, start the electrolyte circulation device, and circulate at a rate of 15L / h to ensure uniform electrolyte concentration distribution. S23. Start the electrochemical deposition instrument, set the current density to 20mA / cm², the deposition temperature to 35℃, and the deposition time to 45min. During the deposition process, monitor the current density and temperature in real time through the numerical control system. If fluctuations occur, automatically adjust to the preset range. At the same time, continuously stir the electrolyte to avoid the generation of concentration gradients.

[0029] S3. Drying and curing: After deposition, turn off the deposition instrument, take out the substrate, rinse it with deionized water 3 times for 3 minutes each time to remove the residual electrolyte on the surface, put it into a CNC oven, set the drying temperature to 110℃, the drying time to 2 hours, control the heating rate at 10℃ / min, and slowly heat up to avoid cracking and peeling of the film. After drying, cool to room temperature to obtain a copper metal film semi-finished product.

[0030] S4. Environmental post-processing: Cleaning, testing, waste material recycling, and packaging of the substrate prepared in step 3. Specifically, this includes: ① Cleaning: Place the semi-finished product in anhydrous ethanol and ultrasonically clean for 5 minutes to remove surface impurities, then air dry naturally; ② Testing: Conductivity was tested using a four-probe tester under the following conditions: room temperature 25℃; film thickness was tested using a film thickness tester; film uniformity was observed using a microscope; and film adhesion was tested using an adhesion tester. ③ Recycling and Packaging: Unqualified products with conductivity <98% pure copper, thickness deviation >5%, or pinholes in the film layer will be redeposited; waste electrolyte will be recycled through a circulation device and can be reused after replenishing raw materials; qualified products will be packaged with anti-static materials and stored in a dry, dust-free environment.

[0031] By focusing on the compatibility of the conductive layer in electronic devices, the conductivity, film uniformity, yield, and energy consumption are tested, compared with the traditional electrochemical deposition method for preparing copper metal films.

[0032] A total of 60 copper metal films were prepared in this experiment, and the test results are as follows: (1) Yield: 57 qualified products and 3 unqualified products (all due to incomplete electrolyte filtration and impurities causing pinholes in the membrane layer), yield was 95%, which is much higher than the 72% of the existing process, verifying the stability of the process of the present invention. (2) Quality parameters: The film thickness is 0.48~0.52μm, with a thickness deviation of 4%, which meets the preset requirements; the film uniformity is excellent, with no pinholes or peeling observed under a microscope, and the particle distribution is uniform; the film adhesion is 23.2N / cm, which is 54.7% higher than that of existing process products; (3) Membrane performance: At room temperature (25℃), the conductivity is 5.8×10^7 S / m, which is 98.3% of the conductivity of pure copper (5.9×10^7 S / m), far exceeding that of existing process products (4.9×10^7 S / m), an improvement of 18.4%; the film layer resistance is uniform with a deviation of ≤3%, meeting the requirements of conductive layers for high-end electronic devices; (4) Energy consumption and cost: The energy consumption per unit product is 110 kWh / ton, which is 42.1% lower than the existing process (190 kWh / ton); the production cost per unit product is 85 yuan, which is 41.4% lower than the existing process of 145 yuan; the waste electrolyte recycling rate is 90%, further saving raw material costs; (5) Analysis: The experimental results show that the copper metal film prepared by the optimized electrochemical deposition process of the present invention has a high yield, uniform film layer, and conductivity close to that of pure copper. The energy consumption and cost are significantly reduced, the operation is simple and environmentally friendly, and it is fully adapted to the preparation requirements of conductive layers of electronic devices. It can replace the existing high-cost copper conductive film preparation process.

[0033] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a metal film by electrochemical deposition, characterized in that, Includes the following steps: Step 1, Raw material pretreatment: Pretreatment of the substrate surface, pretreatment of the anode and preparation of electrolyte, adding a high-efficiency dispersant to the electrolyte for later use; Step 2, Precise Film Deposition: Precise film deposition is performed on the pretreated substrate using electrochemical deposition. The precise film deposition using electrochemical deposition includes the following steps: Step 21: Use the pretreated substrate as the cathode and install it on the cathode holder of the electrochemical deposition instrument. Adjust the distance between the cathode and the anode to make the two electrodes parallel. Step 22: Inject the prepared electrolyte into the sedimentation tank and start the electrolyte circulation device to make the electrolyte concentration distribution uniform. Step 23: Start the electrochemical deposition apparatus, set the current density to 20 mA / cm², the deposition temperature to 35°C, and the deposition time to 45 min. At the same time, continuously stir the electrolyte. Step 3, Drying and curing: After deposition, remove the substrate, remove the residual electrolyte on the surface, put it into a CNC oven, set the drying temperature to 110℃, with a heating rate of 10℃ / min, and a drying time of 2 hours; Step 4, Environmental post-processing: cleaning, testing, waste material recycling and packaging of the substrate prepared in step 3.

2. The method for preparing a metal film by electrochemical deposition according to claim 1, characterized in that, In step 1, the substrate pretreatment includes: immersing the substrate in a 3% hydrofluoric acid solution for 8 minutes to remove the surface oxide layer, rinsing it three times with deionized water for 4 minutes each time, ultrasonically cleaning it in anhydrous ethanol for 10 minutes, removing it and drying it in a 105°C oven for 2 hours, and then cooling it to room temperature.

3. The method for preparing a metal film by electrochemical deposition according to claim 1, characterized in that, In step 1, the anode pretreatment includes: rinsing the pure copper sheet with deionized water, ultrasonically cleaning it in anhydrous ethanol for 5 minutes to remove surface oil, air-drying it naturally, and then installing it on the anode holder of the electrochemical deposition instrument.

4. The method for preparing a metal film by electrochemical deposition according to claim 1, characterized in that, In step 1, the electrolyte preparation includes: adding copper sulfate, sulfuric acid, polyvinyl alcohol, high-efficiency dispersant, and silver nitrate sequentially to deionized water according to a preset ratio, placing the mixture in a constant temperature magnetic stirrer, stirring at 40°C, stirring at 400 r / min, stirring for 1.5 h until completely dissolved, letting it stand for 30 min, filtering with a 0.05 μm pore size filter membrane to remove impurities and undissolved particles, and pouring the mixture into an electrolyte circulation device.

5. The method for preparing a metal film by electrochemical deposition according to claim 1, characterized in that, The highly efficient dispersant is sodium dodecylbenzenesulfonate, with an addition amount of 0.03~0.08 mol / L.

6. The method for preparing a metal film by electrochemical deposition according to claim 1, characterized in that, In step 21, the distance between the cathode and the anode is adjusted to 5 cm.

7. The method for preparing a metal film by electrochemical deposition according to claim 1, characterized in that, In step 22, the circulation rate of the electrolyte circulation device is 15 L / h.

8. The method for preparing a metal film by electrochemical deposition according to claim 1, characterized in that, In step 4, the cleaning process includes: immersing the substrate of the semi-finished product in anhydrous ethanol for ultrasonic cleaning for 5 minutes to remove residual impurities on the surface, and then air-drying it naturally. The tests include: testing the substrate's conductivity, film thickness, film uniformity, and film adhesion. Waste material recycling and packaging: Substandard substrates with conductivity <98% pure copper, film thickness deviation >5%, and pinholes in the film layer are redeposited. Waste electrolyte is recycled through a circulation device and can be reused after replenishing raw materials. Qualified substrates are packaged with anti-static materials and stored in a dry, dust-free environment.

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