Method for enhancing adhesion of composite copper foil and composite copper foil

Abstract

The present application relates to the technical field of metal film, in particular to a method for enhancing the adhesion of composite copper foil and the composite copper foil. The method for enhancing the adhesion of composite copper foil comprises the following steps: using magnetron sputtering to plate a partial oxidation metal film layer on at least one surface of a substrate; using magnetron sputtering or electroplating to plate a copper film layer on the partial oxidation metal film layer, thereby preparing the composite copper foil. The method can effectively improve the adhesion of the film layer and the substrate, improve the plating efficiency, and can complete the preparation of the composite copper foil with the thickness of 1-2 microns of single-sided film at one time. The adhesion of the film layer and the substrate reaches 5B, and the large-scale production can be realized.

Description

Technical Field

[0001] This invention relates to the field of metal thin film technology, and more specifically to a method for enhancing the adhesion of composite copper foil and the composite copper foil. Background Technology

[0002] Composite copper foil serves as both a carrier of the negative electrode active material and a collector and conductor of electrons in lithium-ion batteries, making it a crucial basic material for the negative electrode. With the widespread application of lithium-ion batteries, the market demand for composite copper foil is increasing, leading to upgrades and changes in production equipment and processes. The preparation processes for composite copper foil include chemical electrolytic deposition, evaporation coating, and magnetron sputtering coating. Among these, magnetron sputtering coating offers a good balance between environmental protection and production efficiency, and is therefore widely used.

[0003] Traditional coating equipment has limited coating thickness. When the thickness of a single film exceeds 1μm, it is difficult to achieve one-time coating production. It requires repeated film thickening and surface anti-oxidation treatment processes, which are complex and cumbersome. The film adhesion is low, the production efficiency and equipment utilization are low, and the product yield is difficult to control, which is not conducive to the large-scale production of composite copper foil. Summary of the Invention

[0004] Therefore, it is necessary to provide a method to enhance the adhesion of composite copper foil, so that the composite copper foil obtained by this method has higher film adhesion.

[0005] One aspect of this application provides a method for enhancing the adhesion of composite copper foil, comprising the following steps:

[0006] A partial oxide metal film is deposited on at least one surface of a substrate using magnetron sputtering;

[0007] The composite copper foil is prepared by depositing a copper film layer on the partially oxide metal film layer using magnetron sputtering or electroplating.

[0008] In one embodiment, the composition of the partially oxidized metal film is a complex of elemental metal and metal oxide, and the content of the metal oxide is 40% to 60% by mole percentage.

[0009] In one embodiment, a partial oxide metal film is deposited using a metal target, wherein the metal target includes one or more of titanium, niobium, nickel, molybdenum, chromium, zirconium, aluminum, and silver.

[0010] In one embodiment, during the deposition of a partial oxide metal film, oxygen at a depth of 5 sccm to 10 sccm is introduced into the metal target.

[0011] In one embodiment, the total thickness of the partially oxide metal film and the copper film is 1 μm to 2 μm.

[0012] In one embodiment, the thickness of the partially oxidized metal film is 10 nm to 20 nm.

[0013] In one embodiment, the partial oxide metal film layer is deposited using a medium-frequency power supply with a power of 10kW to 20kW and a voltage of 500V to 550V.

[0014] In one embodiment, the magnetron sputtering power supply used to deposit the copper film layer is 150kW to 200kW, and the voltage is 400V to 550V.

[0015] In another aspect of this application, a composite copper foil is provided, obtained by the method described above for enhancing the adhesion of the composite copper foil.

[0016] In another aspect, this application provides an application of the aforementioned composite copper foil in the preparation of lithium batteries.

[0017] The method for enhancing the adhesion of composite copper foil provided in this application involves depositing a partial metal oxide film layer on at least one surface of a substrate using magnetron sputtering, and then depositing a copper film layer on the partial metal oxide film layer using magnetron sputtering or electroplating. This method effectively improves the adhesion between the film layer and the substrate, increases the coating efficiency, and can complete the preparation of composite copper foil with a single-sided film thickness of 1-2 μm or more in a single operation. Furthermore, the adhesion between the film layer and the substrate reaches 5B, enabling large-scale mass production. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of a composite copper foil according to one embodiment.

[0019] Figure label:

[0020] 100: Substrate; 110: Partially oxidized metal film; 120: Copper film. Detailed Implementation

[0021] To facilitate understanding of the present invention, a more comprehensive description will be given below with reference to embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the present invention.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0023] Magnetron sputtering coating refers to filling a vacuum with a reactive inert gas, such as argon, to induce a glow discharge phenomenon that generates charged ions. These charged ions are accelerated by an electric field and collide with argon atoms in the vacuum, causing the argon atoms to ionize and generate argon ions and new charged ions. Under the acceleration of the electric field and the magnetic field on the back of the target, the target atoms are bombarded and ejected, generating secondary charged ions that collide with argon ions again to form more charged ions. The target atoms carry sufficient kinetic energy to fly to the surface of the coating substrate to deposit and form a film layer.

[0024] Traditional processes deposit a copper layer on a substrate surface using magnetron sputtering as a base layer or seed layer, but the adhesion between the copper layer and the substrate is relatively poor. This application improves the base layer deposition process to enhance the adhesion between the film layer and the substrate without affecting the resistance of the composite copper foil.

[0025] One aspect of this application provides a method for enhancing the adhesion of composite copper foil, comprising the following steps:

[0026] A partial oxide metal film 110 is deposited on at least one surface of a substrate 100 by magnetron sputtering;

[0027] The composite copper foil is prepared by depositing a copper film layer 120 on the partially oxide metal film layer 110 using magnetron sputtering or electroplating.

[0028] In one example, before depositing the partial oxide metal film 110, the process includes an ion cleaning step of ionizing the surface of the substrate 100 using an ion source.

[0029] The partially oxidized metal film 110 is composed of a partially oxidized metal material. Specifically, the partially oxidized metal film 110 is a composite of a metallic element and a metal oxide. Further, in molar percentage, the oxygen content of the metal oxide in the partially oxidized metal film 110 is 40% to 60%.

[0030] In one example, a partial oxide metal film 110 is deposited using a metal target, the metal target including one or more of titanium, niobium, nickel, molybdenum, chromium, zirconium, aluminum and silver.

[0031] Furthermore, during the deposition of the partially oxide metal film 110, oxygen at a flow rate of 5 sccm to 10 sccm is introduced at the location of the metal target. The content of metal oxides in the partially oxide metal film 110 is controlled by the oxygen flow rate. Too much oxygen will result in an excessively high content of metal oxides in the deposited partially oxide metal film 110, reducing the adhesion between the partially oxide metal film 110 and the copper film 120; too little oxygen will result in an excessively low content of metal oxides in the deposited partially oxide metal film 110, approaching complete metallization, thus reducing the adhesion between the partially oxide metal film 110 and the substrate 100.

[0032] During the deposition of the partially oxidized metal film 110, oxygen is introduced into the metal target, and the target's partial oxidation state is determined by the power supply voltage. Specifically, when the power supply is 10KW to 20KW, the target voltage is 500V to 550V. At this voltage, the partial oxidation state is suitable, and the metal oxide content of the deposited partially oxidized metal film 110 can reach 40% to 60% by molar percentage. When the power supply is fixed, the target voltage is adjusted by regulating the oxygen flow rate. When the target voltage is less than 500V, the sputtering is in an over-oxidized state; when the target voltage is greater than 550V, the sputtering is in a metallic state.

[0033] Furthermore, the metal oxide content of the partially oxidized metal film 110 is determined by testing the resistance value. Specifically, when the resistance of the partially oxidized metal film 110 is 1E4–9E4 Ω, the molar percentage of metal oxide is approximately 30%, and the elemental metal is approximately 70%; when the resistance of the partially oxidized metal film 110 is 1E5–2E6 Ω, the molar percentage of metal oxide is approximately 40%, and the elemental metal is approximately 60%; when the resistance of the partially oxidized metal film 110 is 3E6–8E7 Ω, the molar percentage of metal oxide is approximately 50%, and the elemental metal is approximately 50%; when the resistance of the partially oxidized metal film 110 is 9E7–1E9 Ω, the molar percentage of metal oxide is approximately 60%, and the elemental metal is approximately 40%; and when the resistance of the partially oxidized metal film 110 is 1E9–8E10 Ω, the molar percentage of metal oxide is approximately 70%, and the elemental metal is approximately 30%.

[0034] In one example, the partial oxide metal film 110 is deposited using a medium-frequency power supply with a power of 10kW to 20kW and a voltage of 500V to 550V.

[0035] When magnetron sputtering is performed using a medium-frequency power supply, the bombardment energy is high, which can effectively bombard the surface of the substrate 100, activate the surface atoms of the substrate 100, and enable the atoms of the partial oxide metal film 110 to better bond with the substrate 100, thereby improving the bonding force between the partial oxide metal film 110 and the substrate 100.

[0036] In one example, the thickness of the partially oxidized metal film 110 is 10 nm to 20 nm.

[0037] In one example, the total thickness of the partially oxide metal film 110 and the copper film 120 is 1 μm to 2 μm. The film thickness can be adjusted as needed.

[0038] In one example, a copper film layer 120 is deposited on a partially oxide metal film layer 110 by magnetron sputtering using a high-power DC power supply, or by electroplating.

[0039] Specifically, the magnetron sputtering power supply used to deposit the copper film layer 120 is 150kW to 200kW, and the voltage is 400V to 550V.

[0040] In another aspect of this application, a composite copper foil is provided, obtained by the method described above for enhancing the adhesion of the composite copper foil.

[0041] In another aspect, this application provides an application of the aforementioned composite copper foil in the preparation of lithium batteries.

[0042] The method for preparing copper foil provided in this application involves depositing a partial oxide metal film layer 110 on at least one surface of a substrate 100 using magnetron sputtering, and then depositing a copper film layer 120 on the partial oxide metal film layer 110 using magnetron sputtering or electroplating to prepare a composite copper foil. The technical solution of this application improves the magnetron sputtering coating process by integrating multiple steps and making targeted improvements in the sputtering area. This effectively enhances the adhesion between the film layer and the substrate 100, increases coating efficiency, and allows for the one-time preparation of composite copper foil with a single-sided film thickness of 1μm to 2μm. Furthermore, the adhesion between the film layer and the substrate reaches 5B, enabling large-scale mass production.

[0043] In one example, the above method for enhancing the adhesion of composite copper foil includes the following steps:

[0044] S110: Ion cleaning of the surface of substrate 100 using an ion source;

[0045] S120: Introduce oxygen at a depth of 5 sccm to 10 sccm at the metal target location, and test the target voltage at 500V to 550V.

[0046] S130: A partially oxide metal film 110 is deposited on at least one surface of the substrate 100 by magnetron sputtering. The partially oxide metal film 110 is deposited using a medium-frequency power supply with a power of 10kW to 20kW and a voltage of 500V to 550V. The content of metal oxide in the partially oxide metal film 110 is 40% to 60% by mole percentage, and the thickness of the partially oxide metal film 110 is 10nm to 20nm.

[0047] S140: A composite copper foil is prepared by depositing a copper film layer 120 on a partially oxide metal film layer 110 by magnetron sputtering using a high-power DC power supply, or by electroplating. The magnetron sputtering power supply used to deposit the copper film layer 120 has a power of 150kW to 200kW and a voltage of 400V to 550V.

[0048] S150: The total thickness of the partially oxidized metal film 110 and the copper film 120 of the above-mentioned composite copper foil is tested to be 1μm to 2μm, and the adhesion between the film and the substrate 100 is 5B.

[0049] The thickness of the partially oxidized metal film 110 was determined by a profilometer or optical simulation method.

[0050] The following specific embodiments further illustrate the method for enhancing the adhesion of composite copper foil provided in this application.

[0051] Example 1

[0052] The method for enhancing the adhesion of composite copper foil provided in this embodiment includes the following steps:

[0053] 1. Ion cleaning of the substrate surface using an ion source.

[0054] 2. Introduce 5 sccm of oxygen into the metal target.

[0055] 3. A partial oxide metal film was deposited on the substrate using magnetron sputtering. A medium-frequency power supply with a power of 12kW was used to deposit the partial oxide metal film, and the test power supply voltage was 550V.

[0056] 4. The resistance of the above-mentioned partial oxide metal film was measured to be 1E5 to 2E6 using a precision high-resistance analyzer. That is, the content of metal oxide is about 40% in molar percentage.

[0057] 5. The thickness of the partial oxide metal film was measured to be 15 nm using a profilometer.

[0058] 6. A copper film layer is deposited on a partially oxide metal film layer by magnetron sputtering using a high-power DC power supply to prepare a composite copper foil. The magnetron sputtering DC power supply used for depositing the copper film layer has a current of 35.8A, a voltage of 473V, and a quantity of 10 power supplies, that is, a total power of 169KW.

[0059] 7. The thickness of the copper film layer of the above composite copper foil was measured to be 1 μm using a step tester.

[0060] 8. The adhesion between the film layer and the substrate in the cross-cut adhesion test is 5B.

[0061] Example 2

[0062] The method for enhancing the adhesion of composite copper foil provided in this embodiment includes the following steps:

[0063] 1. Ion cleaning of the substrate surface using an ion source.

[0064] 2. Introduce 8 sccm of oxygen into the metal target.

[0065] 3. A partial oxide metal film was deposited on the substrate using magnetron sputtering. A medium-frequency power supply with a power of 12kW was used to deposit the partial oxide metal film, and the test power supply voltage was 520V.

[0066] 4. The resistance of the above-mentioned partial oxide metal film was measured to be 3E6 to 8E7 using a precision high-resistance analyzer. That is, the content of metal oxide is about 50% in molar percentage.

[0067] 5. The thickness of the partial oxide metal film was measured to be 15 nm using a profilometer.

[0068] 6. A copper film layer is deposited on a partially oxide metal film layer by magnetron sputtering using a high-power DC power supply to prepare a composite copper foil. The DC power supply used for magnetron sputtering to deposit the copper film layer has a current of 35.8A and a voltage of 473V. Ten power supplies are used, with a total power of 169KW.

[0069] 7. The thickness of the copper film layer of the above composite copper foil was measured to be 1 μm using a step tester.

[0070] 8. The adhesion between the film layer and the substrate in the cross-cut adhesion test is 5B.

[0071] Example 3

[0072] The method for enhancing the adhesion of composite copper foil provided in this embodiment includes the following steps:

[0073] 1. Ion cleaning of the substrate surface using an ion source.

[0074] 2. Introduce 10 sccm of oxygen into the metal target.

[0075] 3. A partial oxide metal film was deposited on the substrate by magnetron sputtering. A medium-frequency power supply with a power of 12kW was used to deposit the partial oxide metal film, and the test power supply voltage was 500V.

[0076] 4. The resistance of the above-mentioned partial oxide metal film was measured to be 9E7 to 1E9 using a precision high-resistance analyzer. That is, the content of metal oxide is about 60% in molar percentage.

[0077] 5. The thickness of the partial oxide metal film was measured to be 15 nm using a profilometer.

[0078] 6. A copper film layer is deposited on a partially oxide metal film layer by magnetron sputtering using a high-power DC power supply to prepare a composite copper foil. The DC power supply used for magnetron sputtering to deposit the copper film layer has a current of 35.8A and a voltage of 473V. Ten power supplies are used, with a total power of 169KW.

[0079] 7. The thickness of the copper film layer of the above composite copper foil was measured to be 1 μm using a step tester.

[0080] 8. The adhesion between the film layer and the substrate in the cross-cut adhesion test is 5B.

[0081] Comparative Example 1

[0082] The composite copper foil provided in this comparative example is basically the same as that in Examples 1-3, except that it does not include the step of introducing oxygen at the metal target location, which leads to changes in the power supply voltage and the resistance of the partially oxidized metal film, i.e., different metal oxide content in the partially oxidized metal film. Specifically, the composite copper foil of this comparative example is obtained by the following method:

[0083] 1. Ion cleaning of the substrate surface using an ion source.

[0084] 2. A partial oxide metal film was deposited on the substrate by magnetron sputtering. A medium-frequency power supply with a power of 12kW was used to deposit the partial oxide metal film, and the test power supply voltage was 650V.

[0085] 3. The resistance of the above-mentioned partial oxide metal film was tested using a precision high-resistance analyzer and found to be 1E3 to 5E3, which means that the content of metal oxide is less than 30% in molar percentage.

[0086] 4. The thickness of the partial oxide metal film was measured to be 15 nm using a profilometer.

[0087] 5. A copper film layer is deposited on a partially oxide metal film layer by magnetron sputtering using a high-power DC power supply to prepare a composite copper foil. The DC power supply used for magnetron sputtering to deposit the copper film layer has a current of 35.8A and a voltage of 473V. Ten power supplies are used, with a total power of 169KW.

[0088] 6. The thickness of the copper film layer of the above composite copper foil was measured to be 1 μm using a step tester.

[0089] 7. The adhesion between the film layer and the substrate in the cross-cut adhesion test is 3B.

[0090] Comparative Example 2

[0091] The composite copper foil provided in this comparative example is basically the same as that in Examples 1-3, except that the oxygen flow rate introduced at the metal target location is different, which leads to changes in the power supply voltage and the resistance of the partially oxidized metal film, i.e., different metal oxide content in the partially oxidized metal film. Specifically, the composite copper foil of this comparative example is obtained by the following method:

[0092] 1. Ion cleaning of the substrate surface using an ion source;

[0093] 2. Introduce 20 sccm of oxygen into the metal target.

[0094] 3. A partial oxide metal film was deposited on the substrate using magnetron sputtering. A medium-frequency power supply with a power of 12kW was used to deposit the partial oxide metal film, and the test power supply voltage was 380V.

[0095] 4. The resistance value of the above-mentioned partial oxide metal film was measured to be 1E11 using a precision high-resistance analyzer, which means that the content of metal oxide is greater than 80% in molar percentage.

[0096] 5. The thickness of the partial oxide metal film was measured to be 15 nm using a step meter or optical simulation.

[0097] 6. A copper film layer is deposited on a partially oxide metal film layer by magnetron sputtering using a high-power DC power supply to prepare a composite copper foil. The DC power supply used for magnetron sputtering to deposit the copper film layer has a current of 35.8A and a voltage of 473V. Ten power supplies are used, with a total power of 169KW.

[0098] 7. The thickness of the copper film layer of the above composite copper foil was measured to be 1 μm using a step tester.

[0099] 8. The adhesion between the film layer and the substrate in the cross-cut adhesion test is 3B.

[0100] Comparative Example 3

[0101] The composite copper foil provided in this comparative example does not include a partial oxide metal film layer, that is, the copper film layer is directly plated on the substrate surface. Specifically, the composite copper foil of this comparative example is obtained by the following method:

[0102] 1. Ion cleaning of the substrate surface using an ion source.

[0103] 2. A copper film layer is deposited on the surface of a substrate by magnetron sputtering using a high-power DC power supply to prepare a composite copper foil. The DC power supply used for magnetron sputtering to deposit the copper film layer has a current of 35.8A and a voltage of 473V. Ten power supplies are used, with a total power of 169KW.

[0104] 3. The thickness of the copper film layer of the above composite copper foil was measured to be 1 μm using a step tester.

[0105] 4. The adhesion between the film layer and the substrate in the cross-cut adhesion test is 2B.

[0106] The adhesion between the film layer and the substrate 100 was determined using the cross-cut adhesion test. The procedure is as follows: The film layer is cut through with a cross-cut adhesion tester, then 3M adhesive tape is applied to the test area. The tape is pressed flat with a finger to ensure no air bubbles. The tape is then pulled quickly and forcefully at approximately a 90° angle to the product. This test is repeated three times, and the integrity of the film layer in the cross-cut area is checked. The adhesion grade is determined as follows: 5B for no film peeling, 4B for less than 5% peeling area, 3B for 5%–15% peeling area, 2B for 15%–35% peeling area, 1B for 35%–65% peeling area, and 0B for more than 65% peeling area.

[0107] The preparation process parameters and performance parameters of the composite copper foils in Examples 1-3 and Comparative Examples 1-3 are recorded in Table 1.

[0108] Table 1

[0109]

[0110] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0111] The above-described embodiments are merely illustrative of several implementation methods of the present invention, facilitating a detailed understanding of the technical solutions of the present invention, but should not be construed as limiting the scope of protection of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention. It should be understood that technical solutions obtained by those skilled in the art based on the technical solutions provided by the present invention through logical analysis, reasoning, or limited experimentation are all within the scope of protection of the appended claims. Therefore, the scope of protection of this invention patent should be determined by the content of the appended claims, and the specification can be used to interpret the content of the claims.

Claims

1. A method for enhancing the adhesion of composite copper foil, characterized in that, Includes the following steps: A partially oxidized metal film is deposited on at least one surface of a substrate using magnetron sputtering. The partially oxidized metal film is composed of a composite of elemental metal and metal oxide, wherein the content of the metal oxide is 40% to 60% by molar percentage. The composite copper foil is prepared by depositing a copper film layer on the partially oxide metal film layer using magnetron sputtering or electroplating.

2. The method for enhancing the adhesion of composite copper foil according to claim 1, characterized in that, A partial oxide metal film is deposited using a metal target, wherein the metal target includes one or more of titanium, niobium, nickel, molybdenum, chromium, zirconium, aluminum, and silver.

3. The method for enhancing the adhesion of composite copper foil according to claim 2, characterized in that, During the deposition of the partial oxide metal film, oxygen at a depth of 5 sccm to 10 sccm is introduced into the metal target.

4. The method for enhancing the adhesion of composite copper foil according to claim 1, characterized in that, The total thickness of the partially oxide metal film and the copper film is 1 μm to 2 μm.

5. The method for enhancing the adhesion of composite copper foil according to claim 1, characterized in that, The thickness of the partially oxidized metal film is 10 nm to 20 nm.

6. The method for enhancing the adhesion of composite copper foil according to claim 1, characterized in that, The partial oxide metal film layer is deposited using a medium-frequency power supply with a power of 10kW~20kW and a voltage of 500V~550V.

7. The method for enhancing the adhesion of composite copper foil according to claim 1, characterized in that, The magnetron sputtering power supply used to deposit the copper film layer is 150kW~200kW, and the voltage is 400V~550V.

8. A composite copper foil, characterized in that, It is obtained by the method for enhancing the adhesion of composite copper foil as described in any one of claims 1 to 7.

9. The application of the composite copper foil according to claim 8 in the preparation of lithium batteries.

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