A method for treating copper foil surface against oxidation and corrosion using magnetron sputtering

Abstract

The invention discloses a method for treating the surface of copper foil with anti-oxidation and anti-corrosion by using magnetron sputtering. The invention improves the morphology of the roughened layer, increases the bonding strength of copper ions between layers, and enhances its ability to resist internal erosion by external substances by combining secondary roughening with magnetron sputtering curing. At the same time, the invention avoids the poor morphology of the roughened layer caused by the tip discharge phenomenon in the roughening process of the general copper foil, which is prone to the occurrence of spikes and the risk of short circuit during current exchange. The anti-oxidation and corrosion-resistant layer is prepared by using magnetron sputtering. Due to the compactness of the magnetron sputtering film, the copper foil also has better anti-oxidation and corrosion resistance, and has a wide range of applications in the copper foil market for PCBs in my country.

Description

Technical Field

[0001] The invention relates to the technical field of copper foil surface treatment, in particular to a method for treating the surface of copper foil against oxidation and corrosion using magnetron sputtering. Background Art

[0002] Copper foil, as an important component of electronic components, is widely used in the manufacture of various electrical appliances. When preparing printed circuit boards (PCBs), copper foil is combined with resin boards. In order to improve the bonding strength of the copper foil and enhance the peeling strength between the copper foil and the resin substrate, the copper foil is often roughened and anti-oxidation treated. However, in the current preparation of copper foil, manufacturers often only pay attention to the effect of roughening on the bonding strength during the roughening process, but pay less attention to the damage to the copper foil morphology and the risks to the electrical properties caused by the roughening process. In addition, the interlayer density of the roughened layer currently prepared is poor. When external oxygen invades, it cannot form a barrier to oxygen corrosion. Once the anti-oxidation layer is damaged, the roughened layer often becomes a weak link in the anti-oxidation of the copper foil, causing oxidation peeling. In addition, due to the technical limitations of electroplating itself, when preparing anti-oxidation and corrosion-resistant coatings, the coating density is low, which will affect the anti-oxidation and corrosion resistance of the copper foil. Therefore, the electroplating process also brings many restrictions to the application of copper foil. Summary of the Invention

[0003] The object of the present invention is to provide a method for treating the surface of copper foil to resist oxidation and corrosion by magnetron sputtering, so as to solve the problems raised in the above-mentioned background technology.

[0004] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0005] A method for treating the surface of copper foil for oxidation resistance and corrosion resistance using magnetron sputtering, comprising the following steps:

[0006] S1. Place the untreated copper foil in a 10%-15% sulfuric acid solution and clean it with ultrasonic vibration for 10 seconds;

[0007] S2. The primary roughening solution is heated to 40-50°C, and the cleaned copper foil is placed in the primary roughening solution. The roughening current is 25-32A / dm2, and the roughening time is 2.5-3.5s.

[0008] S3. The copper foil after a roughening process was washed with deionized water, heated and dried, and placed in a magnetron sputtering machine to sputter the solidified layer;

[0009] S4. The sputtered solidified layer of copper foil is placed in a secondary roughening solution, the secondary roughening solution temperature is 45-50 ° C, the roughening current is 30-35A / dm2, and the roughening time is 2-3s;

[0010] S5. Replace the sputtering target in the magnetron sputtering machine with an oxidation-resistant and corrosion-resistant target, and sputter one or more oxidation-resistant and corrosion-resistant layers on the copper foil;

[0011] S6. Use silane coupling agent solution to coat the surface of the copper foil by spraying.

[0012] Furthermore, the Cu 2+ The concentration is 10-20g / L, H2SO4 is 120-200g / L, HEC is 5mg / L, and ammonium molybdate is 10-15g / L.

[0013] Copper foil, as an important component of electronic components, is widely used in the manufacture of various electrical appliances. When preparing printed circuit boards (PCBs), copper foil will be combined with resin boards. In order to improve the bonding strength of the copper foil and enhance the peel strength between the copper foil and the resin substrate, the copper foil often needs to undergo a roughening process. By passing current through the copper foil and the electrolyte, a layer of copper is deposited on the surface of the copper foil, thereby increasing the surface area of ​​the copper foil, thereby increasing the contact area with the resin substrate and improving the bonding strength.

[0014] The traditional roughening process uses arsenide as an additive to improve the crystallization behavior of copper ions in the roughening solution on the surface of the copper foil during roughening, thereby achieving the purpose of improving the performance of the prepared roughened layer. The present invention removes the arsenic compounds contained in the roughening solution when preparing the primary roughening layer, reducing the damage of the roughening solution to the environment, and makes the components in the roughening solution appear as low-concentration copper and high-concentration acid. Under these conditions, the copper foil is electroplated to prepare the primary roughening layer.

[0015] The sulfuric acid in the roughening solution can refine the grains generated on the copper foil, improve power efficiency, maintain the stability of the system in the electrolyte, and prevent the current density from decreasing due to low current efficiency in the electrolyte, which makes the copper ion reduction strength in the roughening solution insufficient, resulting in a loose structure of the roughening layer and the risk of copper powder falling off the surface of the copper foil.

[0016] In the present invention, ammonium molybdate is used to replace the role of arsenic compounds in the roughening solution. The molybdate particles in the ammonium molybdate can condense into condensed acid in the electrolyte to form polymetallic oxyacid particles, which can assist in adjusting the complex structure in the roughening solution. In addition, the charge density of molybdenum ions and copper ions differs greatly, and a stable charge transfer complex can be formed between the two, causing the charge valence of the copper ions to change, so that they can be deposited on the copper foil surface more quickly.

[0017] Furthermore, in step S3, the sputtering process of the solidified layer is as follows:

[0018] S31 using acetone solution to clean the copper target with a purity of 99.99%, and then place it in an oven at 80-120 ° C for drying;

[0019] S32. The copper target is mounted on the sputtering device, the target distance is 15-20cm;

[0020] S33. Evacuate the sputtering equipment and adjust the background vacuum to 0.1-1×10 -4 Pa, filled with high-purity argon gas to make the working pressure 0.3-0.8Pa;

[0021] S34. Sputter the copper foil with a sputtering power of 5-8 kW and a machine speed of 5-10 m / min. After sputtering, remove the copper foil.

[0022] Furthermore, in the secondary roughening solution, Cu 2+ The concentration is 8-15g / L, the concentration of H2SO4 is 70-90g / L, the concentration of polyvinyl pyrrolidone is 3-4g / L, and the concentration of sodium polyoxyethylene alkylphenol sulfonate is 2-3g / L.

[0023] After the preparation of the first roughening layer, the surface area of ​​the copper foil has been greatly improved. At this time, the microscopic surface of the copper foil will show a peak-valley structure. However, due to the existence of the tip discharge phenomenon, the copper ions in the first roughening solution will be concentrated and deposited at the tips of the peaks and valleys, resulting in spikes and unevenness. Therefore, the copper foil needs to be subjected to a secondary roughening process to improve this phenomenon.

[0024] When preparing the secondary roughening layer, the present invention adds polyvinyl pyrrolidone and sodium polyoxyethylene alkylphenol sulfonate to the secondary roughening liquid. The two surfactants are used together to reduce the surface tension of the solidified layer, making the hydrogen evolution reaction at the cathode more likely to occur. In addition, a double electric layer is formed on the surface of the substrate to increase the potential, and the grains of the solidified layer are refined, so that the potential on the surface of the copper foil tends to be uniform, avoiding concentrated tip discharge. Therefore, during the secondary roughening process, uniform copper particles can be deposited on the surface of the copper foil, achieving the purpose of reducing coarsened copper dendrites, reducing roughness, and increasing specific surface area.

[0025] In addition, the present invention also adopts high current electroplating when preparing the secondary roughening layer. During electroplating, as the current density increases, the polarization of the cathode is strengthened, and the generation rate of metal grains will be greater than the growth rate, thereby leading to the refinement of the grains and avoiding the property changes caused by large crystals.

[0026] Furthermore, in step S5, the anti-oxidation and corrosion-resistant layer is sputtered by:

[0027] S51. Use acetone solution to clean the antioxidant and corrosion-resistant target, and then place it in an oven at 80-120 ° C for drying;

[0028] S52. The target is mounted on the sputtering device, with a target distance of 10-12 cm;

[0029] S53. The sputtering equipment is evacuated, the background vacuum is adjusted to 0.1-1 × 10-4Pa, and the purity is filled with 99.995% high-purity argon gas to a working pressure of 0.2-0.4Pa;

[0030] S54. Place the copper foil substrate in the sputtering device, turn on the device, and pre-sputter for 3-6 minutes;

[0031] S55. After the pre-sputtering is completed, the copper foil is sputtered with a sputtering power of 2-3kW and a machine speed of 2-10m / min.

[0032] Furthermore, in step S51, the anti-oxidation and corrosion-resistant layer may be one layer or multiple layers, and the target material may be any one of Ni, Zn, Cr, and Co, and the purity of any target material may be ≥99.99%.

[0033] Furthermore, in step S7, the silane coupling agent solution is a silane coupling agent aqueous solution with a concentration of 70%, wherein the silane coupling agent is a mixture of KH-550 and KH-560 in any proportion.

[0034] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: the present invention improves the morphology of the roughened layer, increases the bonding strength of copper ions between layers, and enhances its resistance to internal corrosion by external substances through a method of combining secondary roughening with magnetron sputtering curing; at the same time, it avoids the poor morphology of the roughened layer caused by the tip discharge phenomenon in the general copper foil roughening process, which is prone to spikes and the risk of short circuit during current exchange; and by using magnetron sputtering to prepare the antioxidant and corrosion-resistant layer, the density of the magnetron sputtering film also brings better antioxidant and corrosion resistance to the copper foil, which has a wide range of applications in my country's PCB copper foil market. DETAILED DESCRIPTION

[0035] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0036] Example 1

[0037] S1. Place the untreated copper foil in a 10% sulfuric acid solution and clean it with 20 kHz ultrasonic oscillation for 10 seconds;

[0038] S2. Heat the primary roughening solution to 50°C and place the cleaned copper foil in the primary roughening solution at a roughening current of 25A / dm. 2 , the coarsening time is 3.5s;

[0039] In one of the coarsening solutions, Cu 2+ The concentration is 15g / L, H2SO4 is 120g / L, HEC is 5mg / L, and ammonium molybdate is 10g / L;

[0040] S3. The copper foil after a roughening process was washed with deionized water, heated and dried, and placed in a magnetron sputtering machine to sputter the solidified layer;

[0041] Wherein, the sputtering process of the solidified layer is:

[0042] S31. A copper target with a purity of 99.99% was cleaned with an acetone solution and then dried in an oven at 80°C.

[0043] S32. The copper target is mounted on the sputtering device with a target distance of 15 cm;

[0044] S33. Evacuate the sputtering equipment and adjust the background vacuum to 1×10 -4 Pa, filled with high-purity argon gas to make the working pressure 0.5Pa;

[0045] S34. Sputter the copper foil with a sputtering power of 8 kW and a machine speed of 8 m / min. After the sputtering is completed, remove the copper foil.

[0046] S4. Place the sputtered solidified copper foil in a secondary roughening solution at a temperature of 50°C and a roughening current of 35A / dm 2 , the coarsening time is 2.5s;

[0047] Among them, in the secondary roughening solution, Cu 2+ The concentration is 10g / L, the concentration of H2SO4 is 90g / L, the concentration of polyvinyl pyrrolidone is 3g / L, and the concentration of sodium polyoxyethylene alkylphenol sulfonate is 2g / L;

[0048] S5. Replace the sputtering target in the magnetron sputtering machine with an oxidation-resistant and corrosion-resistant target, and sputter one or more oxidation-resistant and corrosion-resistant layers on the copper foil;

[0049] The sputtering process of the anti-oxidation and corrosion-resistant layer is as follows:

[0050] S51. The Cr target having a purity of 99.99% was cleaned with an acetone solution and then dried in an oven at 80°C.

[0051] S52. The target is mounted on the sputtering device with a target distance of 10 cm;

[0052] S53. Evacuate the sputtering equipment and adjust the background vacuum to 1×10 -4 Pa, filled with 99.995% high-purity argon gas, so that the working pressure is 0.3Pa;

[0053] S54. Place the copper foil substrate in the sputtering device, turn on the device, and pre-sputter for 3 minutes;

[0054] S55. After the pre-sputtering is completed, the copper foil is sputtered with a sputtering power of 3 kW and a machine speed of 3 m / min.

[0055] S6. Use a 70% concentration of KH-550 silane coupling agent solution to coat the surface of the copper foil by spraying, and the finished product can be obtained after drying.

[0056] Example 2

[0057] Compared with Example 1, the electroplating time in S2 and S4 is shortened in this embodiment.

[0058] S1. Place the untreated copper foil in a 10% sulfuric acid solution and clean it with 20KHz ultrasonic oscillation for 10s;

[0059] S2. Heat the primary roughening solution to 50°C and place the cleaned copper foil in the primary roughening solution at a roughening current of 25A / dm. 2 , the coarsening time is 2.5s;

[0060] In one of the coarsening solutions, Cu 2+ The concentration is 15g / L, H2SO4 is 120g / L, HEC is 5mg / L, and ammonium molybdate is 10g / L;

[0061] S3. The copper foil after a roughening process was washed with deionized water, heated and dried, and placed in a magnetron sputtering machine to sputter the solidified layer;

[0062] Wherein, the sputtering process of the solidified layer is:

[0063] S31. A copper target with a purity of 99.99% was cleaned with an acetone solution and then dried in an oven at 80°C.

[0064] S32. The copper target is mounted on the sputtering device with a target distance of 15 cm;

[0065] S33. Evacuate the sputtering equipment and adjust the background vacuum to 1×10 -4 Pa, filled with high-purity argon gas to make the working pressure 0.5Pa;

[0066] S34. Sputter the copper foil with a sputtering power of 8 kW and a machine speed of 8 m / min. After the sputtering is completed, remove the copper foil.

[0067] S4. Place the sputtered solidified copper foil in a secondary roughening solution at a temperature of 50°C and a roughening current of 35A / dm 2 , the coarsening time is 2s;

[0068] Among them, in the secondary roughening solution, Cu 2+ The concentration is 10g / L, the concentration of H2SO4 is 90g / L, the concentration of polyvinyl pyrrolidone is 3g / L, and the concentration of sodium polyoxyethylene alkylphenol sulfonate is 2g / L;

[0069] S5. Replace the sputtering target in the magnetron sputtering machine with an oxidation-resistant and corrosion-resistant target, and sputter an oxidation-resistant and corrosion-resistant layer on the copper foil;

[0070] The sputtering process of the anti-oxidation and corrosion-resistant layer is as follows:

[0071] S51. The Cr target having a purity of 99.99% was cleaned with an acetone solution and then dried in an oven at 80°C.

[0072] S52. The target is mounted on the sputtering device with a target distance of 10 cm;

[0073] S53. Evacuate the sputtering equipment and adjust the background vacuum to 1×10 -4 Pa, filled with 99.995% high-purity argon gas, so that the working pressure is 0.3Pa;

[0074] S54. Place the copper foil substrate in the sputtering device, turn on the device, and pre-sputter for 3 minutes;

[0075] S55. After the pre-sputtering is completed, the copper foil is sputtered with a sputtering power of 3 kW and a machine speed of 3 m / min.

[0076] S6. Use a 70% concentration of KH-550 silane coupling agent solution to coat the surface of the copper foil by spraying, and the finished product can be obtained after drying.

[0077] Example 3

[0078] Compared with Example 1, in this example, Zn and Ni are plated before Cr plating.

[0079] S1. Place the untreated copper foil in a 10% sulfuric acid solution and clean it with 20 kHz ultrasonic oscillation for 10 seconds;

[0080] S2. Heat the primary roughening solution to 50°C and place the cleaned copper foil in the primary roughening solution at a roughening current of 25A / dm.2 , the coarsening time is 3.5s;

[0081] In one of the coarsening solutions, Cu 2+ The concentration is 15g / L, H2SO4 is 120g / L, HEC is 5mg / L, and ammonium molybdate is 10g / L;

[0082] S3. The copper foil after a roughening process was washed with deionized water, heated and dried, and placed in a magnetron sputtering machine to sputter the solidified layer;

[0083] Wherein, the sputtering process of the solidified layer is:

[0084] S31. A copper target with a purity of 99.99% was cleaned with an acetone solution and then dried in an oven at 80°C.

[0085] S32. The copper target is mounted on the sputtering device with a target distance of 15 cm;

[0086] S33. Evacuate the sputtering equipment and adjust the background vacuum to 1×10 -4 Pa, filled with high-purity argon gas to make the working pressure 0.5Pa;

[0087] S34. Sputter the copper foil with a sputtering power of 8 kW and a machine speed of 8 m / min. After the sputtering is completed, remove the copper foil.

[0088] S4. Place the sputtered solidified copper foil in a secondary roughening solution at a temperature of 50°C and a roughening current of 35A / dm 2 , the coarsening time is 2.5s;

[0089] Among them, in the secondary roughening solution, Cu 2+ The concentration is 10g / L, the concentration of H2SO4 is 90g / L, the concentration of polyvinyl pyrrolidone is 3g / L, and the concentration of sodium polyoxyethylene alkylphenol sulfonate is 2g / L;

[0090] S5. Replace the sputtering target in the magnetron sputtering machine with an oxidation-resistant and corrosion-resistant target, and sputter an oxidation-resistant and corrosion-resistant layer on the copper foil;

[0091] The sputtering process of the anti-oxidation and corrosion-resistant layer is as follows:

[0092] S51. A Zn target having a purity of 99.99% was cleaned with an acetone solution and then dried in an oven at 80°C.

[0093] S52. The target is mounted on the sputtering device with a target distance of 10 cm;

[0094] S53. Evacuate the sputtering equipment and adjust the background vacuum to 1×10 -4Pa, filled with 99.995% high-purity argon gas, so that the working pressure is 0.3Pa;

[0095] S54. Place the copper foil substrate in the sputtering device, turn on the device, and pre-sputter for 3 minutes;

[0096] S55. After the pre-sputtering is completed, the copper foil is sputtered with a sputtering power of 3 kW and a machine speed of 4 m / min.

[0097] S6 repeats step S5, the sputtering target is replaced with a Ni target with a purity of 99.99%, the sputtering power is 4kW, and the speed is 5m / min;

[0098] S7 repeats step S5, the sputtering target is replaced with a Cr target with a purity of 99.99%, the sputtering power is 3kW, and the speed is 3m / min;

[0099] S8. Use a 70% concentration of KH-550 silane coupling agent solution to coat the surface of the copper foil by spraying, and the finished product can be obtained after drying.

[0100] Example 4

[0101] Compared with Example 1, in this example, Zn is plated before Cr plating.

[0102] S1. Place the untreated copper foil in a 10% sulfuric acid solution and clean it with 20 kHz ultrasonic oscillation for 10 seconds;

[0103] S2. Heat the primary roughening solution to 50°C and place the cleaned copper foil in the primary roughening solution at a roughening current of 25A / dm. 2 , the coarsening time is 3.5s;

[0104] In one of the coarsening solutions, Cu 2+ The concentration is 15g / L, H2SO4 is 120g / L, HEC is 5mg / L, and ammonium molybdate is 10g / L;

[0105] S3. The copper foil after a roughening process was washed with deionized water, heated and dried, and placed in a magnetron sputtering machine to sputter the solidified layer;

[0106] Wherein, the sputtering process of the solidified layer is:

[0107] S31. A copper target with a purity of 99.99% was cleaned with an acetone solution and then dried in an oven at 80°C.

[0108] S32. The copper target is mounted on the sputtering device with a target distance of 15 cm;

[0109] S33. Evacuate the sputtering equipment and adjust the background vacuum to 1×10-4 Pa, filled with high-purity argon gas to make the working pressure 0.5Pa;

[0110] S34. Sputter the copper foil with a sputtering power of 8 kW and a machine speed of 8 m / min. After the sputtering is completed, remove the copper foil.

[0111] S4. Place the sputtered solidified copper foil in a secondary roughening solution at a temperature of 50°C and a roughening current of 35A / dm 2 , the coarsening time is 2.5s;

[0112] Among them, in the secondary roughening solution, Cu 2+ The concentration is 10g / L, the concentration of H2SO4 is 90g / L, the concentration of polyvinyl pyrrolidone is 3g / L, and the concentration of sodium polyoxyethylene alkylphenol sulfonate is 2g / L;

[0113] S5. Replace the sputtering target in the magnetron sputtering machine with an oxidation-resistant and corrosion-resistant target, and sputter an oxidation-resistant and corrosion-resistant layer on the copper foil;

[0114] The sputtering process of the anti-oxidation and corrosion-resistant layer is as follows:

[0115] S51. A Zn target having a purity of 99.99% was cleaned with an acetone solution and then dried in an oven at 80°C.

[0116] S52. The target is mounted on the sputtering device with a target distance of 10 cm;

[0117] S53. Evacuate the sputtering equipment and adjust the background vacuum to 1×10 -4 Pa, filled with 99.995% high-purity argon gas, so that the working pressure is 0.3Pa;

[0118] S54. Place the copper foil substrate in the sputtering device, turn on the device, and pre-sputter for 3 minutes;

[0119] S55. After the pre-sputtering is completed, the copper foil is sputtered with a sputtering power of 3 kW and a machine speed of 4 m / min.

[0120] S6 repeats step S5, the sputtering target is replaced with a Cr target with a purity of 99.99%, the sputtering power is 3kW, and the speed is 3m / min;

[0121] S7. Use a 70% concentration of KH-550 silane coupling agent solution to coat the surface of the copper foil by spraying, and the finished product can be obtained after drying.

[0122] Example 5

[0123] Compared with Example 1, Zn and Ni are plated before Cr plating in this embodiment, and the amount of Zn and Ni is less than that in Example 3.

[0124] S1. Place the untreated copper foil in a 10% sulfuric acid solution and clean it with 20 kHz ultrasonic oscillation for 10 seconds;

[0125] S2. Heat the primary roughening solution to 50°C and place the cleaned copper foil in the primary roughening solution at a roughening current of 25A / dm. 2 , the coarsening time is 3.5s;

[0126] In one of the coarsening solutions, Cu 2+ The concentration is 15g / L, H2SO4 is 120g / L, HEC is 5mg / L, and ammonium molybdate is 10g / L;

[0127] S3. The copper foil after a roughening process was washed with deionized water, heated and dried, and placed in a magnetron sputtering machine to sputter the solidified layer;

[0128] Wherein, the sputtering process of the solidified layer is:

[0129] S31. A copper target with a purity of 99.99% was cleaned with an acetone solution and then dried in an oven at 80°C.

[0130] S32. The copper target is mounted on the sputtering device with a target distance of 15 cm;

[0131] S33. Evacuate the sputtering equipment and adjust the background vacuum to 1×10 -4 Pa, filled with high-purity argon gas to make the working pressure 0.5Pa;

[0132] S34. Sputter the copper foil with a sputtering power of 8 kW and a machine speed of 8 m / min. After the sputtering is completed, remove the copper foil.

[0133] S4. Place the sputtered solidified copper foil in a secondary roughening solution at a temperature of 50°C and a roughening current of 35A / dm 2 , the coarsening time is 2.5s;

[0134] Among them, in the secondary roughening solution, Cu 2+ The concentration is 10g / L, the concentration of H2SO4 is 90g / L, the concentration of polyvinyl pyrrolidone is 3g / L, and the concentration of sodium polyoxyethylene alkylphenol sulfonate is 2g / L;

[0135] S5. Replace the sputtering target in the magnetron sputtering machine with an oxidation-resistant and corrosion-resistant target, and sputter an oxidation-resistant and corrosion-resistant layer on the copper foil;

[0136] The sputtering process of the anti-oxidation and corrosion-resistant layer is as follows:

[0137] S51. A Zn target having a purity of 99.99% was cleaned with an acetone solution and then dried in an oven at 80°C.

[0138] S52. The target is mounted on the sputtering device with a target distance of 10 cm;

[0139] S53. Evacuate the sputtering equipment and adjust the background vacuum to 1×10 -4 Pa, filled with 99.995% high-purity argon gas, so that the working pressure is 0.3Pa;

[0140] S54. Place the copper foil substrate in the sputtering device, turn on the device, and pre-sputter for 3 minutes;

[0141] S55. After the pre-sputtering is completed, the copper foil is sputtered with a sputtering power of 3 kW and a machine speed of 6 m / min.

[0142] S6 repeats step S5, the sputtering target is replaced with a Ni target with a purity of 99.99%, the sputtering power is 4kW, and the speed is 8m / min;

[0143] S7 repeats step S5, the sputtering target is replaced with a Cr target with a purity of 99.99%, the sputtering power is 3kW, and the speed is 3m / min;

[0144] S8. Use a 70% concentration of KH-550 silane coupling agent solution to coat the surface of the copper foil by spraying, and the finished product can be obtained after drying.

[0145] Comparative Example 1

[0146] Compared with Example 1, in this comparative example, no solidified layer is provided between the primary roughened layer and the secondary roughened layer. Instead, the solidified layer is prepared on the secondary roughened layer by electroplating.

[0147] S1. Place the untreated copper foil in a 10% sulfuric acid solution and clean it with 20 kHz ultrasonic oscillation for 10 seconds;

[0148] S2. Heat the primary roughening solution to 50°C and place the cleaned copper foil in the primary roughening solution at a roughening current of 25A / dm. 2 , the coarsening time is 3.5s;

[0149] S3. Place the copper foil in the secondary roughening solution. The secondary roughening solution temperature is 50°C and the roughening current is 35A / dm 2 , the coarsening time is 2.5s;

[0150] Among them, in the secondary roughening solution, Cu 2+The concentration is 10g / L, the concentration of H2SO4 is 90g / L, the concentration of polyvinyl pyrrolidone is 3g / L, and the concentration of sodium polyoxyethylene alkylphenol sulfonate is 2g / L;

[0151] S4. Place the copper foil after secondary roughening in the curing liquid. 2+ The concentration is 40g / L, H2SO4 is 120g / L, and the curing current is 10A / dm 2 .

[0152] S5. The sputtering target material in the magnetron sputtering machine is an oxidation-resistant and corrosion-resistant target material, which sputters an oxidation-resistant and corrosion-resistant layer on the copper foil;

[0153] The sputtering process of the anti-oxidation and corrosion-resistant layer is as follows:

[0154] S51. The Cr target having a purity of 99.99% was cleaned with an acetone solution and then dried in an oven at 80°C.

[0155] S52. The target is mounted on the sputtering device with a target distance of 10 cm;

[0156] S53. Evacuate the sputtering equipment and adjust the background vacuum to 1×10 -4 Pa, filled with 99.995% high-purity argon gas, so that the working pressure is 0.3Pa;

[0157] S54. Place the copper foil substrate in the sputtering device, turn on the device, and pre-sputter for 3 minutes;

[0158] S55. After the pre-sputtering is completed, the copper foil is sputtered with a sputtering power of 3 kW and a machine speed of 3 m / min.

[0159] S6. Use a 70% concentration of KH-550 silane coupling agent solution to coat the surface of the copper foil by spraying, and the finished product can be obtained after drying.

[0160] Comparative Example 2

[0161] Compared with Example 1, no secondary roughening layer is provided in this comparative example.

[0162] S1. Place the untreated copper foil in a 10% sulfuric acid solution and clean it with 20 kHz ultrasonic oscillation for 10 seconds;

[0163] S2. Heat the primary roughening solution to 50°C and place the cleaned copper foil in the primary roughening solution at a roughening current of 25A / dm. 2 , the coarsening time is 3.5s;

[0164] In one of the coarsening solutions, Cu 2+The concentration is 15g / L, H2SO4 is 120g / L, HEC is 5mg / L, and ammonium molybdate is 10g / L;

[0165] S3. The copper foil after a roughening process was washed with deionized water, heated and dried, and placed in a magnetron sputtering machine to sputter the solidified layer;

[0166] Wherein, the sputtering process of the solidified layer is:

[0167] S31. A copper target with a purity of 99.99% was cleaned with an acetone solution and then dried in an oven at 80°C.

[0168] S32. The copper target is mounted on the sputtering device with a target distance of 15 cm;

[0169] S33. Evacuate the sputtering equipment and adjust the background vacuum to 1×10 -4 Pa, filled with high-purity argon gas to make the working pressure 0.5Pa;

[0170] S34. Sputter the copper foil with a sputtering power of 8 kW and a machine speed of 8 m / min. After the sputtering is completed, remove the copper foil.

[0171] S4. Replace the sputtering target in the magnetron sputtering machine with an oxidation-resistant and corrosion-resistant target, and sputter an oxidation-resistant and corrosion-resistant layer on the copper foil;

[0172] The sputtering process of the anti-oxidation and corrosion-resistant layer is as follows:

[0173] S41. The Cr target having a purity of 99.99% was cleaned with an acetone solution and then dried in an oven at 80°C.

[0174] S42. The target is mounted on the sputtering device with a target distance of 10 cm;

[0175] S43. Evacuate the sputtering equipment and adjust the background vacuum to 1×10 -4 Pa, filled with 99.995% high-purity argon gas, so that the working pressure is 0.3Pa;

[0176] S44. Place the copper foil substrate in the sputtering device, turn on the device, and pre-sputter for 3 minutes;

[0177] S45. After the pre-sputtering is completed, the copper foil is sputtered with a sputtering power of 3 kW and a machine speed of 3 m / min.

[0178] S5. Use a 70% concentration of KH-550 silane coupling agent solution to coat the surface of the copper foil by spraying, and the finished product can be obtained after drying.

[0179] Comparative Example 3

[0180] Compared with Example 1, this comparative example does not use magnetron sputtering to prepare the solidified layer and the anti-oxidation and corrosion-resistant layer.

[0181] S1. Place the untreated copper foil in a 10% sulfuric acid solution and clean it with 20 kHz ultrasonic oscillation for 10 seconds;

[0182] S2. Heat the primary roughening solution to 50°C and place the cleaned copper foil in the primary roughening solution at a roughening current of 25A / dm. 2 , the coarsening time is 3.5s;

[0183] In one of the coarsening solutions, Cu 2+ The concentration is 15g / L, H2SO4 is 120g / L, HEC is 5mg / L, and ammonium molybdate is 10g / L;

[0184] S3. Place the copper foil after the primary roughening in the curing liquid. 2+ The concentration is 40g / L, H2SO4 is 120g / L, and the curing current is 10A / dm 2 .

[0185] S4. Place the solidified copper foil in a secondary roughening solution at a temperature of 50°C and a roughening current of 35A / dm 2 , the coarsening time is 2.5s;

[0186] Among them, in the secondary roughening solution, Cu 2+ The concentration is 10g / L, the concentration of H2SO4 is 90g / L, the concentration of polyvinyl pyrrolidone is 3g / L, and the concentration of sodium polyoxyethylene alkylphenol sulfonate is 2g / L;

[0187] S5. Place the copper foil after secondary roughening in a passivation solution with a Cr concentration of 3-8 g / L and a passivation current of 10 A / dm 2 .

[0188] S6. Use a 70% concentration of KH-550 silane coupling agent solution to coat the surface of the copper foil by spraying, and the finished product can be obtained after drying.

[0189] Comparative Example 4

[0190] Compared with Example 1, no anti-oxidation and corrosion-resistant layer was prepared in this comparative example.

[0191] S1. Place the untreated copper foil in a 10% sulfuric acid solution and clean it with 20 kHz ultrasonic oscillation for 10 seconds;

[0192] S2. Heat the primary roughening solution to 50°C and place the cleaned copper foil in the primary roughening solution at a roughening current of 25A / dm. 2 , the coarsening time is 3.5s;

[0193] In one of the coarsening solutions, Cu 2+ The concentration is 15g / L, H2SO4 is 120g / L, HEC is 5mg / L, and ammonium molybdate is 10g / L;

[0194] S3. The copper foil after a roughening process was washed with deionized water, heated and dried, and placed in a magnetron sputtering machine to sputter the solidified layer;

[0195] Wherein, the sputtering process of the solidified layer is:

[0196] S31. A copper target with a purity of 99.99% was cleaned with an acetone solution and then dried in an oven at 80°C.

[0197] S32. The copper target is mounted on the sputtering device with a target distance of 15 cm;

[0198] S33. Evacuate the sputtering equipment and adjust the background vacuum to 1×10 -4 Pa, filled with high-purity argon gas to make the working pressure 0.5Pa;

[0199] S34. Sputter the copper foil with a sputtering power of 8 kW and a machine speed of 8 m / min. After the sputtering is completed, remove the copper foil.

[0200] S4. Place the sputtered solidified copper foil in a secondary roughening solution at a temperature of 50°C and a roughening current of 35A / dm 2 , the coarsening time is 2.5s;

[0201] Among them, in the secondary roughening solution, Cu 2+ The concentration is 10g / L, the concentration of H2SO4 is 90g / L, the concentration of polyvinyl pyrrolidone is 3g / L, and the concentration of sodium polyoxyethylene alkylphenol sulfonate is 2g / L;

[0202] S5. Use a 70% concentration of KH-550 silane coupling agent solution to coat the surface of the copper foil by spraying, and the finished product can be obtained after drying.

[0203] The product was tested according to GB / T 29847-2013. The results are shown in the table below.

[0204]

[0205] By comparing Examples 1-3, it can be found that the surface roughness of the product prepared by the present invention is moderate, and there is no phenomenon of too low or too high roughness, and the mechanical properties are good.

[0206] By comparing Examples 1, 3, 4, and 5 with Comparative Example 4, it is found that Cr and Ni have better corrosion resistance, and Zn has better high-temperature oxidation resistance; the combination of multiple metal sputtering layers can achieve oxidation resistance and corrosion resistance; and after multi-layer sputtering, the surface roughness can be improved.

[0207] By comparing Example 1 with Comparative Example 1, it was found that when the solidified layer was not prepared by sputtering, the oxidation resistance and corrosion resistance of the copper foil were retained, but its mechanical properties were reduced.

[0208] By comparing Example 1 with Comparative Example 2, it was found that when the roughening layer and the solidified layer were prepared only once, the corrosion resistance and mechanical properties of the copper foil were reduced.

[0209] By comparing Example 1 with Comparative Example 3, it was found that the copper foil in which the solidified layer and the passivation layer were prepared by electroplating had poor mechanical properties, with various physical characteristics declining to varying degrees, and insufficient antioxidant and corrosion resistance.

[0210] By comparing Examples 1 and 3 with Comparative Example 4, it is found that the sputtering passivation layer prepared by the present invention has excellent performance in improving the oxidation resistance and corrosion resistance of the copper foil, and also plays an important role in the anti-stripping ability of the copper foil.

[0211] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art will be able to modify the technical solutions described in the aforementioned embodiments or substitute equivalents for some of the technical features. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A method for treating copper foil surface for anti-oxidation and corrosion resistance using magnetron sputtering, characterized in that: The following steps are involved: S1. Place the untreated copper foil in a 10%-15% sulfuric acid solution and clean it with ultrasonic vibration for 10 seconds; S2. Heat the primary roughening solution to 40-50°C and place the cleaned copper foil in the primary roughening solution. The roughening current is 25-32A / dm 2 , the coarsening time is 2.5-3.5s; S3. The copper foil after a roughening process was washed with deionized water, heated and dried, and placed in a magnetron sputtering machine to sputter the solidified layer; S4. Place the sputtered solidified copper foil in a secondary roughening solution at a temperature of 45-50°C and a roughening current of 30-35A / dm 2 , the coarsening time is 2-3s; S5. Replace the sputtering target in the magnetron sputtering machine with an oxidation-resistant and corrosion-resistant target, and sputter one or more oxidation-resistant and corrosion-resistant layers on the copper foil; S6. Coating the copper foil surface with a silane coupling agent solution by spraying; In step S3, the sputtering process of the solidified layer is as follows: S31 using acetone solution to clean the copper target with a purity of 99.99%, and then place it in an oven at 80-120 ° C for drying; S32. The copper target is mounted on the sputtering device, the target distance is 15-20cm; S33. Evacuate the sputtering equipment and adjust the background vacuum to 0.1-1×10 -4 Pa, filled with high-purity argon gas to make the working pressure 0.3-0.8Pa; S34 sputtering operation of the copper foil, the sputtering power is 5-8kW, the speed is 5-10m / min, after the sputtering is completed, the copper foil is removed; In step S5, the sputtering process of the anti-oxidation and corrosion-resistant layer is as follows: S51. Use acetone solution to clean the antioxidant and corrosion-resistant target, and then place it in an oven at 80-120 ° C for drying; S52. The target is mounted on the sputtering device, with a target distance of 10-12 cm; S53. Evacuate the sputtering equipment and adjust the background vacuum to 0.1-1×10 -4 Pa, filled with 99.995% high-purity argon gas, so that the working pressure is 0.2-0.4Pa; S54. Place the copper foil substrate in the sputtering device, turn on the device, and pre-sputter for 3-6 minutes; S55. After the pre-sputtering is completed, the copper foil is sputtered at a sputtering power of 2-3kW and a machine speed of 2-10m / min; The Cu 2+ The concentration is 10-20g / L, H2SO4 is 120-200g / L, HEC is 5mg / L, and ammonium molybdate is 10-15g / L; In the secondary roughening solution, Cu 2+ The concentration is 8-15g / L, the concentration of H2SO4 is 70-90g / L, the concentration of polyvinyl pyrrolidone is 3-4g / L, and the concentration of sodium polyoxyethylene alkylphenol sulfonate is 2-3g / L.

2. The method for treating the surface of copper foil for oxidation resistance and corrosion resistance using magnetron sputtering according to claim 1, wherein: In step S5, one or more layers of anti-oxidation and corrosion-resistant metal layers may be sputtered; the anti-oxidation and corrosion-resistant target material may be any one of Ni, Zn, Cr, and Co, and the purity of any of the target materials may be ≥99.99%.

3. The method for treating the surface of copper foil for oxidation resistance and corrosion resistance using magnetron sputtering according to claim 1, wherein: In step S6, the silane coupling agent solution is a silane coupling agent aqueous solution with a concentration of 70%, wherein the silane coupling agent is a mixture of KH-550 and KH-560 in any proportion.

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