Electrode and use thereof

Abstract

An electrode and uses thereof. The electrode comprises a substrate, a catalytic layer and a protective layer, wherein the catalytic layer is selected from a mixed metal oxide layer and the protective layer is selected from an organic ionomer layer; a surface coating can be further included between the catalytic layer and the protective layer; and an intermediate layer may be further included between the substrate and the catalytic layer. The electrode can be used as an anode for surface processing applications.

Description

Technical Field

[0001] This application relates to, but is not limited to, the field of electrochemistry, and more particularly to, but not limited to, electrodes and their uses. Background Art

[0002] Printed circuit boards are a major component of electronic devices and are widely used as a connection carrier for integrated electronic devices and other equipment. Electroplating, such as vertical continuous plating (VCP), is a common method for preparing printed circuit boards.

[0003] In the application of VCP of copper for printed circuit boards, metal electrodes with mixed metal oxide (MMO) coatings are conventionally used as anodes, and additives such as carriers, brighteners, and leveling agents are usually required. These additives can achieve a fine-grained, non-oriented copper grain structure and a uniform copper thickness. In this case, for MMO-coated anodes, it is necessary to prevent the contact of metal (e.g., Ir) active sites with additive molecules to avoid additive consumption. Compared with Cu-P alloy anodes, MMO-coated anodes have a much higher additive consumption rate. Summary of the Invention

[0004] The following is an overview of the subject matter described in detail herein. This overview is not intended to limit the scope of protection of the claims.

[0005] In order to reduce the additive consumption rate and lower the production cost, the inventors of this application have improved the MMO-coated electrodes through years of careful research.

[0006] This application provides an electrode comprising a substrate, a catalytic layer, and a protective layer; wherein the catalytic layer may be selected from mixed metal oxide layers; and the protective layer may be selected from organic ionomer layers, such as fluororesin layers, such as sulfonated tetrafluoroethylene layers, such as Nafion.

[0007] In some embodiments, a surface coating may be further included between the catalytic layer and the protective layer, and the surface coating may be selected from Ta oxide layers, such as Ta 2 O 5 layers.

[0008] In some embodiments, an intermediate layer may be further included between the substrate and the catalytic layer, and the intermediate layer may be selected from Ta oxide layers, Ti oxide layers, Ti-Ta mixed metal oxide layers, Ti-Ta alloy layers, or Ti-Pd alloy layers.

[0009] In some embodiments, the catalytic layer and the surface coating may be multiple layers stacked alternately.

[0010] In some embodiments, the loading of the protective layer can be 1 g / m 2 to 10 g / m 2 and can also be 2 g / m 2 to 5 g / m 2 .

[0011] In some embodiments, the Ta content in the surface coating can be 1 g / m 2 to 20 g / m 2 and can also be 10 g / m 2 to 15 g / m 2 .

[0012] In some embodiments, the catalytic layer can be selected from a Ru-Ti mixed metal oxide layer, an Ir-Ti mixed metal oxide layer, a Ru-Ir-Ti mixed metal oxide layer, a Ru-Ta mixed metal oxide layer, an Ir-Ta mixed metal oxide layer, a Ru-Ir-Ta mixed metal oxide layer, or a Pt-Ir mixed metal oxide layer.

[0013] In some embodiments, the content of Ti, Ta, or Pt in the catalytic layer can be 10 wt% to 80 wt% of the total mass of the metal elements and can also be 20 wt% to 70 wt%.

[0014] In some embodiments, the loading of Ru, Ir, or Pt in the catalytic layer can be 2 g / m 2 to 20 g / m 2 and can also be 5 g / m 2 to 10 g / m 2 and can also be 6 g / m 2 to 8 g / m 2 .

[0015] In some embodiments, the Ta content in the intermediate Ti-Ta mixed metal oxide layer can be not less than 10 wt% of the total mass of the metal elements, can also be not less than 20 wt% of the total mass of the metal elements, and can further be 40 wt% to 50 wt% of the total mass of the metal elements.

[0016] In some embodiments, the Ta content in the intermediate Ti-Ta alloy layer can be not less than 10 wt% of the total mass of the alloy, can also be not less than 20 wt% of the total mass of the alloy, and can further be 40 wt% to 50 wt% of the total mass of the alloy.

[0017] In some embodiments, the Pd content in the intermediate Ti-Pd alloy layer can be 0.01 wt% to 0.25 wt% of the total mass of the alloy and can also be 0.12 wt% to 0.25 wt% of the total mass of the alloy.

[0018] In some embodiments, the loading amount of Ta in the intermediate Ta oxide layer, the intermediate Ti-Ta mixed metal oxide layer, and the intermediate Ti-Ta alloy layer can be 1 g / m 2 to 10 g / m 2 and can also be 4 g / m 2 or 5 g / m 2 .

[0019] In some embodiments, the loading amount of Ti in the intermediate Ti oxide layer and the intermediate Ti-Pd alloy layer can be 1 g / m 2 to 10 g / m 2 and can also be 4 g / m 2 or 5 g / m 2 .

[0020] In some embodiments, the substrate can be selected from metal Ti, Ta, Nb, or their alloys.

[0021] The present application further provides the use of the above electrode, where the electrode can be used as an anode for surface processing applications, can also be used as an anode for electroplating, and can further be used as an anode for copper electroplating or an anode for vertical continuous electroplating.

[0022] In some embodiments, electroplating can be used to prepare printed circuit boards.

[0023] Other features and advantages of the present application will be elaborated in the following description. Other advantages of the present application can be achieved and obtained through the solutions described in the specification and the drawings. After reading and understanding the drawings and the specific embodiments, other aspects will become clear. Description of the Drawings

[0024] The drawings are used to provide an understanding of the technical solutions of the present application and constitute a part of the specification. They are used to explain the technical solutions of the present application together with the embodiments of the present application and do not constitute a limitation on the technical solutions of the present application.

[0025] Figure 1 is a scanning electron microscope photograph of the substrate titanium mesh of the electrode prepared in Example 1;

[0026] Figure 2 is a scanning electron microscope photograph of the top view of the protective layer of the electrode prepared in Example 1. Detailed Description of the Embodiments

[0027] The embodiments of the present application will be described in detail below with reference to the drawings. It should be noted that as long as there is no conflict, the embodiments in the present application and the features in the embodiments can be combined with each other arbitrarily.

[0028] Embodiments of the present application provide an electrode. For example, the electrode includes a substrate, a catalytic layer, and a protective layer stacked in sequence from bottom to top. The protective layer can effectively prevent the contact between additive molecules and metal active sites and exhibit chemical inertia during the oxygen evolution process, thereby greatly reducing the additive consumption rate.

[0029] It is also feasible to symmetrically arrange the catalytic layer and the protective layer on both sides of the substrate, or to arrange the catalytic layer and the protective layer on one side of the substrate and only arrange the catalytic layer on the other side of the substrate. The catalytic layer provides electrochemically activity for the oxygen evolution reaction and has properties such as abrasion resistance and catalyst corrosion stability.

[0030] A surface coating may or may not be provided between the catalytic layer and the protective layer. The surface coating can provide a better interface for the adhesion of the protective layer, thereby improving the bonding between the protective layer and the catalytic layer.

[0031] An intermediate layer may or may not be provided between the substrate and the catalytic layer. The intermediate layer has good corrosion resistance and can provide additional corrosion protection for the substrate.

[0032] The catalytic layer and the surface coating can be multiple layers stacked alternately.

[0033] The substrate can be selected from metals Ti, Ta, Nb, or their alloys. For example, it can be metallic titanium (Ti); it can also be commercially pure titanium (e.g., ASTM grade 1 or ASTM grade 2 commercially pure titanium); and it can further be a Ti-based alloy (e.g., ASTM grade 7 or ASTM grade 11 titanium alloy), such as a Ti-Nb alloy containing a small amount of Nb, a Ti-Ta alloy containing a small amount of Ta, or a Ti-Nb-Ta alloy containing a small amount of Nb and Ta, for example, the total content of Nb and Ta does not exceed 5 wt% of the total mass of the alloy. The substrate can be a mesh, plate, foam, felt, etc., for example, it can be a metallic titanium mesh.

[0034] The intermediate layer can be selected from Ta oxide, Ti oxide, Ti-Ta mixed metal oxide, Ti-Ta alloy or Ti-Pd alloy. The Ta content in the Ti-Ta mixed metal oxide layer can be not less than 10 wt% of the total mass of metal elements, can also be not less than 20 wt% of the total mass of metal elements, and can further be 40 wt% to 50 wt% of the total mass of metal elements. For example, the mass ratio of Ta to Ti can be 40:60, 50:50, etc. The Ta content in the Ti-Ta alloy can be not less than 10 wt% of the total mass of the alloy, can also be not less than 20 wt% of the total mass of the alloy, and can further be 40 wt% to 50 wt% of the total mass of the alloy. For example, the mass ratio of Ta to Ti can be 40:60, 50:50, etc. The Pd content in the Ti-Pd alloy layer can be 0.01 wt% to 0.25 wt% of the total mass of the alloy, and can also be 0.12 wt% to 0.25 wt% of the total mass of the alloy. For example, the Pd content can be 0.15 wt%, 0.18 wt%, 0.20 wt%, etc. The loading amount of Ta in the Ta oxide layer, Ti-Ta mixed metal oxide layer and Ti-Ta alloy layer can be 1 g / m 2 to 10 g / m 2 , for example, 4 g / m 2 , 5 g / m 2 , etc. The loading amount of Ti in the Ti oxide layer and Ti-Pd alloy layer can be 1 g / m 2 to 10 g / m 2 , for example, 4 g / m 2 or 5 g / m 2 ; or the loading amount of Pd in the Ti-Pd alloy layer can be 0.1 mg / m 2 to 25 mg / m 2 , for example 1 mg / m 2 , 5 mg / m 2 , 10 mg / m 2 , 15 mg / m 2 , etc.

[0035] The intermediate layer can be prepared by a wet chemical method or a vapor deposition method (such as a magnetron sputtering method, a chemical vapor deposition method, etc.). The use of the magnetron sputtering method can enable the formation of a dense intermediate layer on the substrate, which improves the corrosion resistance.

[0036] In an example of the magnetron sputtering method, the temperature of the substrate is controlled to be 200 °C to 400 °C, an inert gas is used as the sputtering gas, the vacuum degree is 0.1 Pa to 0.5 Pa, the power of the DC power supply is 100 W to 500 W, the target-substrate distance is 30 mm to 100 mm, and the required loading amount is obtained by controlling the ratio of the target materials used simultaneously and adjusting the sputtering time.

[0037] The catalytic layer can be selected from a Ru-Ti mixed metal oxide layer, an Ir-Ti mixed metal oxide layer, a Ru-Ir-Ti mixed metal oxide layer, a Ru-Ta mixed metal oxide layer, an Ir-Ta mixed metal oxide layer, a Ru-Ir-Ta mixed metal oxide layer, or a Pt-Ir mixed metal oxide layer. The content of Ti, Ta or Pt in the catalytic layer can be 10 wt% to 80 wt% of the total mass of the metal elements, and can also be 20 wt% to 70 wt%, for example, 30 wt%, 40 wt%, 50 wt%, 60 wt%, etc. The loading of Ru, Ir or Pt in the catalytic layer can be 2 g / m 2 to 20 g / m 2 and can also be 5 g / m 2 to 10 g / m 2 and can also be 6 g / m 2 to 8 g / m 2 for example, 7 g / m 2 etc. The catalytic layer provides electrochemically activity for the oxygen evolution reaction and has properties such as abrasion resistance and catalyst corrosion stability.

[0038] The catalytic layer can be prepared by methods such as coating-thermal decomposition, chemical vapor deposition (e.g., atomic layer deposition (ALD)), plasma-thermal spraying, and physical vapor deposition. In an example of coating-thermal decomposition, the catalytic layer is formed through the following steps: coating a coating solution containing, for example, Ru and Ti, a coating solution containing Ir and Ti, a coating solution containing Ru, Ir and Ti, a coating solution containing Ru and Ta, a coating solution containing Ir and Ta, a coating solution containing Ru, Ir and Ta, or a coating solution containing Pt and Ir on the surface of a substrate or an intermediate layer, followed by drying and thermal decomposition. The coating-thermal decomposition process can be carried out several times until the desired loading is obtained.

[0039] The surface coating can be an oxide of tantalum, for example, it can be Ta 2 O 5 . The Ta content in the surface coating can be 1 g / m 2 to 20 g / m 2 and can also be 10 g / m 2 to 15 g / m 2 for example, 11 g / m 2 12 g / m 2 13 g / m 2 14 g / m 2 etc.

[0040] The surface coating can be prepared by methods such as sol-gel thermal decomposition, chemical vapor deposition (e.g., ALD), plasma thermal spraying, and physical vapor deposition. In an example of sol-gel thermal decomposition, a surface coating is formed by coating a paint solution containing Ta on the surface of the catalytic layer, followed by drying and thermal decomposition. This sol-gel thermal decomposition process can be carried out several times until the desired loading is obtained.

[0041] The protective layer can be an organic ionomer, for example, it can be a fluororesin, for example, it can further be sulfonated tetrafluoroethylene, and for example, it can further be Nafion. The loading of the protective layer can be 1 g / m 2 to 10 g / m 2 , and it can also be 2 g / m 2 to 5 g / m 2 , for example, 3 g / m 2 , 4 g / m 2 , etc.

[0042] The protective layer can be prepared by methods such as sol-gel thermal decomposition, chemical vapor deposition (e.g., ALD), plasma thermal spraying, and physical vapor deposition.

[0043] The electrode of the present application is suitable for use as an anode for electroplating, especially as an anode for copper electroplating or as an anode for vertical continuous electroplating for the preparation of printed circuit boards.

[0044] The present application has the following beneficial effects:

[0045] 1. The electrode of the present application has a dense protective layer (e.g., a fluororesin layer), which can effectively prevent the contact between additive molecules and metal active sites, and exhibits chemical inertia during the oxygen evolution process, greatly reducing the additive consumption rate.

[0046] 2. The protective layer of the present application can also provide ionic conductivity, thereby reducing the resistance of the coating to ionic current.

[0047] 3. The combination of the protective layer and the surface coating (e.g., Ta 2 O 5 layer) in the electrode of the present application achieves a synergistic effect, enabling the protective layer to better adhere to the surface coating, which is more beneficial for reducing the additive consumption rate.

[0048] 4. The electrode of the present application has a simple preparation method and reduced production cost, which is beneficial for large-scale production.

[0049] Example 1

[0050] Use metallic titanium (Ti) as the electrode substrate. Select a titanium mesh with a grid factor of 2.0 and a thickness of 2 mm that meets the requirements of ASTM - B265 grade 1, and then sandblast it with iron sand and pickle it with sulfuric acid.

[0051] Form an Ir - Ta MMO catalytic layer on the substrate, where the loading amount of Ir is 5 g / m 2 . Aqueous iridium chloride solution and tantalum pentachloride salt are used to prepare a n - butanol solution with an iridium mass concentration of 3 wt%, where the mass ratio of iridium element to tantalum element is 65:35. Apply this solution to the surface of the substrate with a brush. Each time when 1 g of iridium is applied per square meter of the coating, dry the substrate at 80 °C and decompose it at 500 °C for 10 minutes, and then take it out for cooling and continue coating until the iridium loading target of 5 g / m 2 is achieved.

[0052] Form a Ta 2 O 5 surface coating on the catalytic layer, where the loading amount of Ta is 10 g / m 2 . Tantalum pentachloride salt is used to prepare a n - butanol solution with a tantalum mass concentration of 3 wt%. Apply this solution to the surface of the catalytic layer with a brush. Each time when 1 g of tantalum is applied per square meter of the coating, dry the object at 80 °C and decompose it at 500 °C for 10 minutes, and then take it out for cooling and continue coating until the tantalum loading target of 10 g / m 2 is achieved.

[0053] Form a fluororesin protective layer on the surface coating, where the loading amount of fluororesin is 2 g / m 2 . Prepare an isopropanol solution containing 5 wt% Nafion. Apply this solution to the surface of the surface coating with a brush. Each time when 1 g of fluororesin is applied per square meter of the coating, cure the object, and then take it out for cooling and continue coating until the fluororesin loading amount of 2 g / m 2 is achieved.

[0054] Thus, the electrode is prepared.

[0055] Example 2

[0056] Use the same metallic titanium (Ti) as in Example 1 as the electrode substrate.

[0057] Use the same steps as in Example 1 to form an Ir - Ta MMO catalytic layer on the substrate, where the loading amount of Ir is 5 g / m 2 .

[0058] Use the same steps as in Example 1 to form a fluororesin protective layer on the catalytic layer, where the loading amount of fluororesin is 5 g / m 2 .

[0059] The electrode was prepared therefrom.

[0060] Example 3

[0061] The same metallic titanium (Ti) as in Example 1 was used as the electrode substrate.

[0062] An Ir-Ta MMO catalytic layer was formed on the substrate using the same procedure as in Example 1, where the loading amount of Ir was 5 g / m 2 .

[0063] A Ta 2 O 5 surface coating was formed on the catalytic layer using the same procedure as in Example 1, where the loading amount of Ta was 1 g / m 2 .

[0064] A second Ir-Ta MMO catalytic layer was formed on the surface coating using the same procedure as in Example 1, where the loading amount of Ir was 1 g / m 2 .

[0065] A second Ta 2 O 5 surface coating was formed on the second catalytic layer using the same procedure as in Example 1, where the loading amount of Ta was 10 g / m 2 .

[0066] A fluororesin protective layer was formed on the second surface coating using the same procedure as in Example 1, where the loading amount of the fluororesin was 5 g / m 2 .

[0067] The electrode was prepared therefrom.

[0068] Comparative Example 1

[0069] The same metallic titanium (Ti) as in Example 1 was used as the electrode substrate.

[0070] An Ir-Ta MMO catalytic layer was formed on the substrate using the same procedure as in Example 1, where the loading amount of Ir was 5 g / m 2 .

[0071] The electrode was prepared therefrom.

[0072] Comparative Example 2

[0073] The same metallic titanium (Ti) as in Example 1 was used as the electrode substrate.

[0074] An Ir-Ta MMO catalytic layer was formed on the substrate using the same procedure as in Example 1, where the loading amount of Ir was 5 g / m 2 .

[0075] Ta was formed on the catalytic layer using the same steps as in Example 1 2 O 5 surface coating, where the loading of Ta is 10 g / m 2 .

[0076] The electrode was thus prepared.

[0077] Electrode microstructure

[0078] The electrode prepared in Example 1 was tested by scanning electron microscopy.

[0079] The substrate of the electrode is shown in Figure 1 and the substrate is in a grid shape.

[0080] The protective layer of the electrode is shown in Figure 2 . As can be seen from Figure 2 , the protective layer is a dense structure. The dense protective layer can effectively prevent the contact between additive molecules and metal active sites, and exhibits chemical inertia during the oxygen evolution process, thus greatly reducing the additive consumption rate.

[0081] Test of additive consumption rate

[0082] The additive consumption rates of the electrodes obtained in the test examples and comparative test examples were tested. The test results are shown in Table 1:

[0083] Table 1 Additive consumption rate

[0084]

[0085] Note: "EVF-B" is an additive used for continuous copper electroplating in the manufacture of printed circuit boards.

[0086] As can be seen from Table 1, the additive consumption rates of the electrodes in Examples 1 - 3 of the present application (with fluororesin protective layers) are lower than those of the electrodes in Comparative Examples 1 - 2 (without fluororesin protective layers). Specifically, the additive consumption rate in Example 3 is only 78 mL / KAh, which is about one-tenth of the additive consumption rate in Comparative Example 1. The main reason is that the fluororesin is denser, which can effectively prevent the contact between additive molecules and Ir active sites, and exhibits chemical inertia during the oxygen evolution process.

[0087] In addition, in Example 2 of the present application, the additive consumption rate can still be effectively reduced when the surface coating is not included and only the fluororesin protective layer is included. Therefore, it can be seen that the fluororesin protective layer is the key factor for reducing the additive consumption rate.

[0088] In addition, even when the fluororesin loading amount in Example 1 is less than that in Example 2, the additive consumption rate in Example 1 is still lower than that in Example 2. The main reason is that the combination of the surface coating Ta 2 O 5 and the protective layer fluororesin produces a synergistic effect, and they can be better combined, which is more beneficial for reducing the additive consumption rate.

[0089] As can be further seen from Table 1, the additive consumption rate in Example 3 is even lower, indicating that alternately stacking the MMO layer and the surface coating can achieve better results in reducing the additive consumption rate.

[0090] Although the embodiments disclosed in this application are as described above, the content described is only an embodiment adopted for the convenience of understanding this application and is not used to limit this application. Any person skilled in the art to which this application pertains can make any modifications and changes to the implementation forms and details without departing from the spirit and scope disclosed in this application. However, the scope of patent protection of this application should still be subject to the scope defined by the appended claims.

Claims

1. An electrode, which comprises a substrate, a catalytic layer and a protective layer, wherein the catalytic layer is selected from mixed metal oxide layers; the protective layer is selected from organic ionomer layers, preferably fluororesin layers, and more preferably sulfonated tetrafluoroethylene layers.

2. The electrode according to claim 1, wherein the electrode further comprises a surface coating between the catalytic layer and the protective layer, and the surface coating is selected from Ta oxide layers, preferably Ta 2 O 5 layers.

3. The electrode according to claim 1 or 2, wherein the electrode further comprises an intermediate layer between the substrate and the catalytic layer, and the intermediate layer is selected from Ta oxide layers, Ti oxide layers, Ti-Ta mixed metal oxide layers, Ti-Ta alloy layers, or Ti-Pd alloy layers.

4. The electrode according to any one of claims 1-3, wherein, the catalytic layer and the surface coating are multiple layers stacked alternately.

5. The electrode according to any one of claims 1-3, wherein, The loading amount of the protective layer is 1 g / m 2 to 10 g / m 2 and preferably 2 g / m 2 to 5 g / m 2 .

6. The electrode according to any one of claims 2-5, wherein, The Ta content in the surface coating is 1 g / m 2 to 20 g / m 2 and preferably 10 g / m 2 to 15 g / m 2 .

7. The electrode according to any one of claims 1-6, wherein, the catalytic layer is selected from Ru-Ti mixed metal oxide layers, Ir-Ti mixed metal oxide layers, Ru-Ir-Ti mixed metal oxide layers, Ru-Ta mixed metal oxide layers, Ir-Ta mixed metal oxide layers, Ru-Ir-Ta mixed metal oxide layers, or Pt-Ir mixed metal oxide layers.

8. The electrode according to claim 7, wherein, the content of Ti, Ta or Pt in the catalytic layer is 10 wt% to 80 wt% of the total mass of metal elements, preferably 20 wt% to 70 wt%.

9. The electrode according to claim 7 or 8, wherein, The loading amount of Ru, Ir or Pt in the catalytic layer is 2 g / m 2 to 20 g / m 2 Preferably, it is 5 g / m 2 to 10 g / m 2 And more preferably, it is 6 g / m 2 to 8 g / m 2 .

10. The electrode according to any one of claims 3-9, wherein, the Ta content in the intermediate layer Ti-Ta mixed metal oxide layer is not less than 10 wt% of the total mass of metal elements, preferably not less than 20 wt%, and more preferably 40 wt% to 50 wt%; the Ta content in the intermediate layer Ti-Ta alloy layer is not less than 10 wt% of the total mass of the alloy, preferably not less than 20 wt%, and more preferably 40 wt% to 50 wt%; and the Pd content in the intermediate layer Ti-Pd alloy is 0.01 wt% to 0.25 wt% of the total mass of the alloy, preferably 0.12 wt% to 0.25 wt%.

11. The electrode according to any one of claims 3-10, wherein, The loading amount of Ta in the intermediate Ta oxide layer, the intermediate Ti-Ta mixed metal oxide layer, and the intermediate Ti-Ta alloy layer is 1 g / m 2 to 10 g / m 2 , preferably 4 g / m 2 or 5 g / m 2 ; and The loading amount of Ti in the intermediate Ti oxide layer and the intermediate Ti-Pd alloy layer is 1 g / m 2 to 10 g / m 2 , preferably 4 g / m 2 or 5 g / m 2 .

12. The electrode according to any one of claims 1-11, wherein, the substrate is selected from metal Ti, Ta, Nb or their alloys.

13. Use of the electrode according to any one of claims 1-12, wherein the electrode is used as an anode for surface processing applications, preferably as an anode for electroplating, and more preferably as an anode for copper electroplating or as an anode for vertical continuous electroplating.

14. The use according to claim 13, wherein, the electroplating is used for preparing printed circuit boards.

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