A production process for synchronously improving the double-sided flatness of copper foil, as well as its product and application

Abstract

The present invention discloses a production process for synchronously improving the double-sided flatness of copper foil, which includes: injecting electrolyte into an electrolytic cell with a cathode roller through a liquid distribution valve, and then injecting separately prepared aqueous solutions of hydroxyethyl cellulose and collagen into the electrolytic cell. After electrolysis, copper foil is prepared; the injection flow rate of the aqueous solution of hydroxyethyl cellulose is 11±2 L / h; the injection flow rate of the aqueous solution of collagen is 8±2 L / h; before electrolysis, the cathode roller is subjected to on-line polishing treatment, and the polishing time is 45 to 70 min. The production process disclosed by the present invention controls the roughness of the smooth surface while regulating the roughness of the matte surface of the copper foil, and prepares electrolytic copper foil specifically for buried resistor copper foil, meeting the performance requirements of matte surface roughness MRz≤2.5μm, smooth surface roughness SRz≥1.3μm, tensile strength≥360 N / mm<supgt;2< / supgt;, and elongation≥6%.

Description

Technical Field

[0001] The present invention belongs to the technical field of electronic material processing, and specifically relates to a production process for synchronously improving the double-sided flatness of copper foil, its products, and their applications in preparing buried resistance copper foil and further in preparing PCBs. Background Art

[0002] In the electronics industry, buried resistance copper foil is widely used in the manufacturing process of printed circuit boards (PCBs). Buried resistance copper foil has good electrical conductivity and mechanical strength and can be used to connect different layers on the circuit board. With the rapid development of communication technology, the Internet of Things, and Internet technology, electronic products are gradually becoming miniaturized, thin, light, intelligent, and multifunctional. As a special conductive material, buried resistance copper foil has unique advantages in meeting these requirements. It can precisely control the current transmission of the PCB by controlling the resistance value, thereby ensuring the stability and reliability of the circuit.

[0003] However, the above applications impose more stringent requirements on the comprehensive performance of resistance copper foil. The resistance copper foil not only needs to have a low matte surface roughness to ensure the high efficiency of signal transmission but also needs to have a high glossy surface roughness to ensure more stable corrosion resistance in downstream processing etching. However, achieving the coordinated improvement of the two is a very challenging task. Summary of the Invention

[0004] In view of the above problems, the present invention discloses a production process for synchronously improving the double-sided flatness of copper foil, which controls the matte surface roughness and the glossy surface roughness of the copper foil at the same time, and prepares electrolytic copper foil dedicated to buried resistance copper foil, meeting the performance requirements of matte surface roughness MRz ≤ 2.5 μm, glossy surface roughness SRz ≥ 1.3 μm, tensile strength ≥ 360 N / mm 2 , elongation ≥ 6%.

[0005] To achieve the above object, the specific technical solutions of the present invention are as follows:

[0006] A production process for synchronously improving the double-sided flatness of copper foil, comprising the following steps:

[0007] Inject copper sulfate electrolyte into an electrolytic cell with a cathode roller, and then inject separately prepared aqueous solutions of hydroxyethyl cellulose and collagen into the electrolytic cell, and prepare copper foil through electrolysis;

[0008] The concentration of the aqueous solution of hydroxyethyl cellulose is 1.0 ± 0.5 g / L, and the injection flow rate is 11 ± 2 L / h;

[0009] The concentration of the aqueous solution of collagen is 1.5 ± 0.5 g / L, and the injection flow rate is 8 ± 2 L / h;

[0010] Before electrolysis, the cathode roller is subjected to on-line polishing treatment, and the polishing time is 45-70 min.

[0011] The production process disclosed by the present invention realizes the effect of synchronously improving the double-sided profile of the copper foil by precisely controlling the polishing time of the on-line polishing treatment of the cathode roller and the respective flow rates of the aqueous hydroxyethyl cellulose solution and the aqueous collagen solution added to the electrolytic solution, so as to reduce the roughness of the matte surface (control MRz ≤ 2.5 μm) while increasing the roughness of the shiny surface (control SRz ≥ 1.3 μm), and ensure the high strength and high ductility of the copper foil (tensile strength ≥ 360 N / mm 2 , elongation ≥ 6%).

[0012] It is found through experiments that if the polishing time is inappropriate, or the respective flow rates of the aqueous hydroxyethyl cellulose solution and the aqueous collagen solution added are too large or too small, the copper foil prepared cannot meet the above performance requirements.

[0013] The copper sulfate electrolytic solution is prepared by adding copper wires with a diameter of 8 mm (copper purity ≥ 99.95%), sulfuric acid with a concentration of 98%, pure water, etc.

[0014] Preferably:

[0015] In the copper sulfate electrolytic solution, the copper ion concentration is 83.5 ± 15 g / L, the H2SO4 concentration is 130 ± 20 g / L, and the chloride ion concentration is 5-25 ppm;

[0016] Further preferably, in the copper sulfate electrolytic solution, the copper ion concentration is 83.5 ± 5 g / L, the H2SO4 concentration is 130 ± 10 g / L, and the chloride ion concentration is 5-15 ppm.

[0017] Preferably:

[0018] The molecular weight of the collagen used in the aqueous collagen solution is not higher than 5000 D; further preferably not higher than 3000 D, and more preferably 1000-3000 D.

[0019] The on-line polishing treatment is carried out with a polishing brush;

[0020] Preferably:

[0021] The mesh number of the polishing brush is 1200 ± 500 mesh, the rotation speed is 220 ± 30 r / min, and the swing speed is 160 ± 30 times / min;

[0022] The pressurized current for on-line polishing is 0.4 ± 0.3 A, and the rotation speed of the cathode roller is 2.2 ± 0.5 m / min.

[0023] For the electrolysis, preferably:

[0024] The upper liquid temperature is 51 ± 3°C, and the upper liquid flow rate is 43 ± 5 m 3 / h;

[0025] The current intensity is 45000 ± 5000 A, and the rotational speed of the cathode roller is 4.721 ± 0.7 m / min.

[0026] It has been found through experiments that the upper liquid temperature will also affect the performance of the prepared electrolytic copper foil. Therefore, the upper liquid temperature needs to be stabilized at 51 ± 3°C.

[0027] The present invention also discloses an electrolytic copper foil prepared according to the above process, and the use of this copper foil for preparing buried resistor copper foil and further application in PCBs.

[0028] For the said copper foil, the tensile strength ≥ 360 N / mm 2 , elongation at break ≥ 6%, MRz ≤ 2.5 μm, SRz ≥ 1.3 μm.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] The present invention proposes a production process for synchronously improving the double-sided flatness of copper foil. By precisely controlling the polishing time of the online polishing treatment of the cathode roller and the respective flow rates of the aqueous hydroxyethyl cellulose solution and the aqueous collagen solution added to the electrolyte, while controlling the roughness of the matte surface of the copper foil, the roughness of the shiny surface is also managed, and an electrolytic copper foil dedicated to buried resistor copper foil is prepared. It has a shiny surface roughness SRZ ≥ 1.3 μm and a matte surface low roughness MRZ ≤ 2.5 μm, which has strong practicality in improving the side etching resistance of the shiny surface of the buried resistor layer and reducing the matte surface flatness of the buried resistor copper foil, and realizes more stable use for preparing buried resistor copper foil. Description of the Drawings

[0031] Figure 1 SEM images of the shiny surface (S surface) and matte surface (M surface) of the copper foil prepared in Example 1;

[0032] Figure 2 SEM images of the shiny surface (S surface) and matte surface (M surface) of the copper foil prepared in Example 2;

[0033] Figure 3 SEM images of the shiny surface (S surface) and matte surface (M surface) of the copper foil prepared in Example 3;

[0034] Figure 4 SEM images of the shiny surface (S surface) and matte surface (M surface) of the copper foil prepared in Example 4;

[0035] Figure 5 SEM images of the shiny surface (S surface) and matte surface (M surface) of the copper foil prepared in Example 5;

[0036] Figure 6SEM images of the smooth surface (S surface) and matte surface (M surface) of the copper foil prepared in Comparative Example 1;

[0037] Figure 7 SEM images of the smooth surface (S surface) and matte surface (M surface) of the copper foil prepared in Comparative Example 2;

[0038] Figure 8 SEM images of the smooth surface (S surface) and matte surface (M surface) of the copper foil prepared in Comparative Example 3;

[0039] Figure 9 SEM images of the smooth surface (S surface) and matte surface (M surface) of the copper foil prepared in Comparative Example 4;

[0040] Figure 10 SEM images of the smooth surface (S surface) and matte surface (M surface) of the copper foil prepared in Comparative Example 5;

[0041] Figure 11 SEM images of the smooth surface (S surface) and matte surface (M surface) of the copper foil prepared in Comparative Example 6. Detailed implementation manners

[0042] The present invention will be further described in detail below in conjunction with examples and comparative examples. However, the implementation manners of the present invention are not limited thereto. The specific implementation methods described herein are only for explaining and interpreting the present invention, and are not used to limit the protection scope of the present invention.

[0043] Unless otherwise specified, the raw materials in the examples of this application are all purchased through commercial channels.

[0044] Example 1

[0045] (1) Add copper wires with a diameter of 8 mm (copper purity ≥ 99.95 wt%), sulfuric acid with a concentration of 98 wt%, pure water, etc. into the copper dissolution tank;

[0046] (2) Adjust the concentrations of various ions required for the copper sulfate electrolyte in the purification tank: copper ion concentration is 85 g / L, H2SO4 concentration is controlled at 130 g / L, and chloride ion concentration is controlled at 10 ppm;

[0047] (3) Add hydroxyethyl cellulose, collagen (molecular weight is 3000 D), and 2 kg of wood powder activated carbon into the waste liquid tank, and circulate for 2 h;

[0048] (4) Inject the electrolyte into the electrolytic cell with a cathode roller through a liquid distribution valve, introduce the prepared hydroxyethyl cellulose aqueous solution with a concentration of 1.0 g / L, and adjust the flow rate to 9 L / h; collagen aqueous solution with a concentration of 1.5 g / L, and adjust the flow rate to 8 L / h;

[0049] (5) Use a plate heat exchanger to adjust and maintain the temperature of the incoming liquid to 50 °C; at the same time, adjust the incoming liquid flow rate to 43 m by controlling the incoming liquid valve3 The level of / h;

[0050] (6) Use a polishing brush with a mesh number of 1200 to perform on-line polishing on the surface of the cathode roll. Set the rotation speed of the polishing brush to 220 r / min, the swing speed to 160 ± 30 times / min, the polishing pressure current to 0.3 A, the rotation speed of the cathode roll to 1.100 m / min, and the polishing time to 60 min;

[0051] (7) After polishing, set the current intensity to 45000 A and the rotation speed of the cathode roll to 4.721 m / min for electrolysis;

[0052] (8) After electrolysis is completed, after pickling, strip the electrolytic copper foil from the cathode roll through a stripping roll.

[0053] The data of preparing the electrolytic copper foil in this embodiment are shown in Table 1.

[0054] Example 2

[0055] (1) Add copper wire with a diameter of 8 mm (copper purity ≥ 99.95%), sulfuric acid with a concentration of 98%, pure water, etc. into the copper melting tank;

[0056] (2) Adjust the concentrations of various ions required for the electrolyte in the purified liquid tank: copper ion 80 g / L, H2SO4 concentration controlled at 128 g / L, and chloride ion concentration controlled at 9 ppm;

[0057] (3) Add hydroxyethyl cellulose, collagen (molecular weight 3000 D), and 2 kg of wood powder activated carbon into the waste liquid tank and circulate for 2 h;

[0058] (4) Inject the electrolyte into the electrolytic cell with a cathode roll through a liquid distribution valve, introduce the prepared aqueous solution of hydroxyethyl cellulose with a concentration of 1.0 g / L, and adjust the flow rate to 13 L / h; aqueous solution of collagen with a concentration of 1.5 g / L, and adjust the flow rate to 10 L / h;

[0059] (5) Use a plate heat exchanger to adjust and maintain the temperature of the incoming liquid to 54 °C; at the same time, adjust the incoming liquid flow rate to 44 m 3 / h level;

[0060] (6) Use a polishing brush with a mesh number of 1200 to perform on-line polishing on the surface of the cathode roll. Set the rotation speed of the polishing brush to 230 r / min, the swing speed to 160 ± 30 times / min, the polishing current to 0.3 A, the rotation speed of the cathode roll to 1.100 m / min, and the polishing time to 65 min;

[0061] (7) After polishing, set the current intensity to 43000 A and the rotation speed of the cathode roll to 4.426 m / min for electrolysis;

[0062] (8) After electrolysis and pickling, the electrolytic copper foil is peeled off from the cathode roller by a stripping roller.

[0063] The data of preparing the electrolytic copper foil in this embodiment are shown in Table 1.

[0064] Example 3

[0065] (1) Add copper wires with a diameter of 8 mm (copper purity ≥ 99.95%), sulfuric acid with a concentration of 98%, pure water, etc. into the copper dissolving tank;

[0066] (2) Adjust the concentrations of various ions required for the electrolyte in the purified liquid tank: copper ion concentration is 79 g / L, H2SO4 concentration is controlled at 133 g / L, and chloride ion concentration is controlled at 11 ppm;

[0067] (3) Add hydroxyethyl cellulose, collagen (molecular weight 3000 D), and 2 kg of wood powder activated carbon into the waste liquid tank and circulate for 2 h;

[0068] (4) Inject the electrolyte into the electrolytic cell with a cathode roller through a liquid distribution valve, introduce the prepared aqueous solution of hydroxyethyl cellulose with a concentration of 1.0 g / L, and adjust the flow rate to 11 L / h; the concentration of the aqueous solution of collagen is 1.5 g / L, and the flow rate is adjusted to 8 L / h;

[0069] (5) Use a plate heat exchanger to adjust and maintain the temperature of the incoming liquid to 51 °C; at the same time, adjust the incoming liquid flow rate to 42 m 3 / h by controlling the incoming liquid valve;

[0070] (6) Use a polishing brush with 1200 mesh to perform on-line polishing on the surface of the cathode roller, set the rotation speed of the polishing brush to 190 r / min, the swing speed to 160 ± 30 times / min, the polishing current to 0.3 A, the rotation speed of the cathode roller to 1.100 m / min, and the polishing time to 70 min;

[0071] (7) After polishing, adjust the current intensity to 50000 A and the rotation speed of the cathode roller to 5.083 m / min for electrolysis;

[0072] (8) After electrolysis and pickling, the electrolytic copper foil is peeled off from the cathode roller by a stripping roller.

[0073] The data of preparing the electrolytic copper foil in this embodiment are shown in Table 1.

[0074] Example 4

[0075] (1) Add copper wires with a diameter of 8 mm (copper purity ≥ 99.95%), sulfuric acid with a concentration of 98%, pure water, etc. into the copper dissolving tank;

[0076] (2) Adjust the concentrations of various ions required for the electrolyte in the purified liquid tank: copper ion 84 g / L, H2SO4 concentration controlled at 126 g / L, and chloride ion concentration controlled at 8 ppm;

[0077] (3) Add hydroxyethyl cellulose, collagen (molecular weight 3000 D), and 2 kg of wood powder activated carbon into the waste liquid tank and circulate for 2 h;

[0078] (4) Inject the electrolyte into the electrolytic cell with a cathode roll through a diverter valve, introduce the prepared aqueous solution of hydroxyethyl cellulose with a concentration of 1.0 g / L, and adjust the flow rate to 10 L / h; aqueous solution of collagen with a concentration of 1.5 g / L, and adjust the flow rate to 6 L / h;

[0079] (5) Use a plate heat exchanger to adjust and maintain the temperature of the incoming liquid to 48 °C; at the same time, adjust the incoming liquid flow rate to 43 m 3 / h by controlling the incoming liquid valve;

[0080] (6) Use a polishing brush with a mesh number of 1200 to perform on-line polishing on the surface of the cathode roll, set the polishing brush rotation speed to 250 r / min, the swing speed to 160 ± 30 times / min, the polishing current to 0.3 A, the cathode roll rotation speed to 1.100 m / min, and the polishing time to 55 min;

[0081] (7) After polishing, adjust the current intensity to 40000 A and the cathode roll rotation speed to 4.196 m / min for electrolysis;

[0082] (8) After electrolysis and pickling, strip the electrolytic copper foil from the cathode roll through a stripping roll.

[0083] The data of preparing the electrolytic copper foil in this example are shown in Table 1.

[0084] Example 5

[0085] The preparation process is basically the same as that in Example 1, except that in step (3):

[0086] Use collagen with an equal mass and a molecular weight of 5000 D.

[0087] Comparative Example 1

[0088] The preparation process is basically the same as that in Example 1, except that in step (4): adjust the flow rate of hydroxyethyl cellulose to 15 L / h (concentration unchanged), and adjust the flow rate of collagen to 11 L / h (concentration unchanged).

[0089] Comparative Example 2

[0090] The preparation process is basically the same as that in Example 1, except that in step (6):

[0091] Replace the polishing time with 40 min.

[0092] Comparative Example 3

[0093] The preparation process is basically the same as that in Example 1, except that in step (5):

[0094] Replace the temperature of the upper liquid with 45 °C.

[0095] Comparative Example 4

[0096] The preparation process is basically the same as that in Example 1, except that:

[0097] In step (5), replace the temperature of the upper liquid with 53 °C;

[0098] In step (6), replace the polishing time with 75 min.

[0099] Comparative Example 5

[0100] The preparation process is basically the same as that in Example 1, except that hydroxyethyl cellulose is not added in step (3).

[0101] Comparative Example 6

[0102] The preparation process is basically the same as that in Example 1, except that hydroxyethyl cellulose is replaced with an equal mass of modified cellulose in step (3).

[0103] The copper foils prepared in each of the examples and comparative examples were tested. Among them, the tensile strength and elongation were tested using a universal material peeling machine and a universal material testing machine respectively, and the matte surface roughness (MRz) and the shiny surface roughness (SRz) were tested using a roughness meter. The specific values are listed in Table 1 below.

[0104] Table 1

[0105] Sample Number <![CDATA[Tensile strength / N / mm 2 > Elongation Rate % MRz (μm) SRz (μm) Control Standard ≥360 ≥6 ≤2.5 ≥1.3 Example 1 364 7 2.26 1.39 Example 2 362 8 2.43 1.40 Example 3 360 7 2.39 1.42 Example 4 364 7 2.32 1.32 Example 5 364 7 2.46 1.34 Comparative Example 1 357 7 2.57 1.32 Comparative Example 2 341 5 2.42 1.08 Comparative Example 3 349 6 2.69 1.32 Comparative Example 4 336 5 3.15 1.40 Comparative Example 5 338 5 3.33 1.38 Comparative Example 6 352 6 2.96 1.32

[0106] It can be seen from Table 1 that the electrolytic copper foils prepared in Examples 1 to 5 all meet the performance requirements of tensile strength ≥ 360 N / mm 2 , elongation ≥ 6%, MRz ≤ 2.5 μm, and SRz ≥ 1.3 μm, and can be used to prepare buried resistance copper foils, and Example 1 is the best example among them. The performance of the electrolytic copper foils prepared in Comparative Examples 1 to 6 does not meet the standards.

[0107] Figures 1 to 11SEM images of the copper foils prepared in Examples 1-5 and Comparative Examples 1-6 respectively. As can be seen from the attached drawings, for the copper foils prepared in Examples 1-5, the number of copper nodules on the matte surface is dense and uniform, and the overall structure is smooth, which is consistent with the data of the lower matte surface roughness (MRz); while on the shiny surface, the shiny surface has a strong bite ability, which is also consistent with the data of the higher shiny surface roughness (SRz).

[0108] Compared with each example, the number of copper nodules on the matte surface of the copper foils prepared in Comparative Examples 1, 3-6 is less, and the mountain shape is non-uniform. For the copper foil prepared in Comparative Example 2, the bite ability of the shiny surface is weak, which is not conducive to improving the corrosion resistance.

[0109] The above-disclosed are the preferred embodiments, but the protection scope of the present invention is not limited thereto. Those of ordinary skill in the art can easily understand the spirit of the present invention based on the above embodiments and make different extensions and changes. However, as long as they do not depart from the spirit of the present invention, they are within the protection scope of the present invention.

Claims

1. A production process for simultaneously improving the double-sided profile of copper foil, characterized in that: The following steps are involved: The copper sulfate electrolyte is injected into an electrolytic cell with a cathode roller, and then the prepared hydroxyethyl cellulose aqueous solution and collagen aqueous solution are injected into the electrolytic cell, and the copper foil is prepared after electrolysis; In the copper sulfate electrolyte, the copper ion concentration is 83.5±15 g / L, the H2SO4 concentration is 130±20 g / L, and the chloride ion concentration is 5~25 ppm; The concentration of the hydroxyethyl cellulose aqueous solution is 1.0±0.5 g / L, and the injection flow rate is 11±2 L / h; The concentration of the collagen aqueous solution is 1.5±0.5 g / L, and the injection flow rate is 8±2 L / h; The molecular weight of the collagen used in the collagen aqueous solution is not higher than 5000D; The upper liquid temperature is 51±3℃; Before electrolysis, the cathode roller is polished online for 45 to 70 minutes; The online polishing process is performed using a polishing brush; The mesh number of the polishing brush is 1200±500 mesh, the rotation speed is 220±30r / min, and the swing speed is 160±30 times / min; The pressure current of online polishing is 0.4±0.3A, and the rotation speed of the cathode roller is 2.2±0.5m / min.

2. The production process for simultaneously improving the double-sided profile of copper foil according to claim 1, characterized in that: The electrolysis: The upper liquid flow rate is 43±5m 3 / h; The current intensity is 45000±5000A, and the cathode roller speed is 4.721±0.7m / min.

3. The production process for simultaneously improving the double-sided profile of copper foil according to claim 1 or 2, characterized in that: The copper foil has a tensile strength of ≥360N / mm 2 , elongation ≥ 6%, MRz ≤ 2.5μm, SRz ≥ 1.3μm.

4. The production process for simultaneously improving the double-sided profile of copper foil according to claim 1 or 2, characterized in that: The copper foil is used for preparing buried barrier copper foil.

5. The production process for simultaneously improving the double-sided profile of copper foil according to claim 4, characterized in that: The buried copper foil is applied in PCB.

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