A continuous conductive film plating apparatus, a conductive film, and a conductive film plating method

Abstract

The application discloses a kind of continuous plating equipment of conductive film, conductive film and its plating method, the equipment includes at least two independent electroplating plating units, electroplating plating unit is provided with independent reagent circulation channel;Base film is successively continuously passed through adjacent electroplating plating unit, and the main salt copper ion concentration in the electroplating plating unit of the rear end of base film driving direction is higher than the main salt copper ion concentration in the electroplating plating unit of the front end of base film driving direction.The application can be individually adjusted and controlled to local main salt copper ion, and there is no component exchange between each other, improve the effectiveness of electroplating, improve the quality of plating and the effect of plating, solve the technical problems of low plating efficiency and unable to individually regulate reagent in the prior art.The electroplating method of the application is beneficial to improve the efficiency and effect of electroplating, increase the thin film deposition rate, and can regulate the surface roughness of plating film layer, meet the electroplating demand of different performance film layer.

Description

Technical Field

[0001] This invention relates to the field of conductive film electroplating technology, and in particular to a continuous conductive film plating equipment, a conductive film, and a plating method thereof. Background Technology

[0002] A current collector is a structure that collects current. In lithium-ion batteries, it mainly refers to the base metal, such as copper foil or aluminum foil, used to attach active materials to the positive or negative electrode. Its function is to collect the current generated by the battery's active materials to form a larger current output. During manufacturing, current collectors are typically produced by electroplating a thick metal layer onto a conductive base film to ensure conductivity. A plating machine is usually used to electroplat the conductive base film.

[0003] Traditional continuous coating equipment systems have a significant characteristic: the coating agent produced by a single line is circulated as a large system and transported to each electroplating unit via related pump sets. In other words, the formulation or proportion of each component of the agent is the same throughout the entire circulation system.

[0004] Therefore, the inventors discovered in the process of realizing this invention that conventional continuous coating equipment cannot achieve ultra-high efficiency thin film deposition by individually controlling the reagents because the reagents are the same throughout the entire coating process. This limits the fine or diversified control of the microstructure and properties of the coated film to a certain extent. Summary of the Invention

[0005] In view of this, the present invention provides a conductive film continuous coating equipment, a conductive film and a coating method thereof, which at least partially solves the technical problems of low coating efficiency and inability to individually control the reagents in the prior art.

[0006] One of the technical solutions to achieve the purpose of this invention is: a conductive film continuous coating equipment, comprising at least two independent electroplating units, wherein each electroplating unit is provided with an independent reagent circulation channel;

[0007] The base film passes through adjacent electroplating units in succession, and the concentration of copper ions in the main salt in the electroplating unit at the rear end of the base film transmission direction is higher than the concentration of copper ions in the electroplating unit at the front end of the base film transmission direction.

[0008] A further preferred embodiment is that the feed end in the base film transmission direction is provided with a cleaning tank for removing impurity elements and capable of online monitoring;

[0009] The impurity removal and cleaning tank is located in front of the electroplating unit at the foremost point in the base film transmission direction.

[0010] A further preferred embodiment is that an isolation cleaning tank is provided between the impurity removal cleaning tank and the electroplating coating unit.

[0011] A further preferred embodiment is that the impurity removal cleaning tank is an acidic tank or an alkaline tank; and the isolation cleaning tank is a water washing tank.

[0012] A further preferred embodiment is that the electroplating unit includes an electroplating tank, a transmission structure located within the electroplating tank and used for driving the base film, an electroplating agent located within the electroplating tank, and a lower electroplating anode and an upper electroplating anode located within the electroplating tank.

[0013] The electroplating agent is connected to a circulation pump in the agent circulation channel;

[0014] An adjustable electroplating gap is provided between the lower electroplating anode and the upper electroplating anode.

[0015] Furthermore, when using insoluble anode plates to assist in copper thin film deposition, the electroplating tank is provided with two insoluble anode plates, one above the other, which serve as the lower electroplating anode and the other above the other; the base film serves as the cathode, used to accept copper ions and reduce them to form a copper film deposition.

[0016] When copper ions are provided by dissolving copper phosphate balls, the electroplating tank is provided with lower copper phosphate balls and upper copper phosphate balls, which serve as the lower electroplating anode and the upper electroplating anode, respectively; the control of the main salt copper ions in each electroplating tank is achieved by one of the following methods: self-dissolution of copper phosphate balls; supply of external copper ions; or a combination of dissolution of copper phosphate balls and supply of external copper ions.

[0017] A further preferred embodiment is that the electroplating spacing in the electroplating unit at the rear end of the base film transmission direction is smaller than the electroplating spacing in the electroplating unit at the front end of the base film transmission direction.

[0018] The smaller the electroplating spacing, the greater the current of the corresponding electroplating unit;

[0019] The electroplating agent in the downstream electroplating unit has a higher current tolerance than the electroplating agent in the upstream electroplating unit, and / or the current density per unit area of ​​the downstream electroplating unit is higher than that of the upstream electroplating unit.

[0020] Further preferably, the electroplating unit with a high concentration of copper ions in the main salt is arranged adjacent to or not adjacent to the electroplating unit with a low concentration of copper ions in the main salt; the reagent circulation channel is also used to replenish copper ions in the correspondingly connected electroplating unit.

[0021] When the distance between the base film and the lower and upper electroplating anodes remains constant, the concentration of copper ions in the main salt increases along the transmission direction of the base film; and / or,

[0022] When the distance between the base film and the lower and upper electroplating anodes decreases with the direction of transmission of the base film, the concentration of copper ions in the main salt increases.

[0023] A further preferred embodiment is that the electroplating agent contained in each individual electroplating unit has a different formulation; and / or,

[0024] In each electroplating unit, adjacent electroplating units may use the same reagent system or different reagent systems;

[0025] When the same reagent system is used, the same reagent system is selected from any one of the following: acidic copper sulfate system, pyrophosphate copper plating system, cyanide copper plating system, and alkaline cyanide-free copper plating system.

[0026] When different reagent systems are used, the different reagent systems are selected from any combination of the following: acidic copper sulfate system, pyrophosphate copper plating system, cyanide copper plating system, and alkaline cyanide-free copper plating system.

[0027] The second technical solution to achieve the objective of this invention is: a continuous conductive film deposition method, comprising the following steps:

[0028] Step A: Real-time detection of the main salt copper ion concentration in the electroplating unit at the rear end of the base film transmission direction and the main salt copper ion concentration in the electroplating unit at the front end of the base film transmission direction, and ensuring that the main salt copper ion concentration in the electroplating unit at the rear end is greater than the main salt copper ion concentration in the electroplating unit at the front end.

[0029] Step B: The base film is continuously passed through the electroplating unit with low main salt copper ion concentration and the electroplating unit with high main salt copper ion concentration in the self-transmission direction.

[0030] Step C: Gradually increase the thickness of the electroplated coating on the base film to complete the electroplating.

[0031] Furthermore, between step B and step C, step D may also be included: adjusting the electroplating spacing between the electroplating cathode and electroplating anode in different electroplating units to increase the electroplating current in the electroplating unit with a high concentration of main salt copper ions.

[0032] A further preferred embodiment is that, in step B, the base film passes through a cleaning tank for impurity removal and a cleaning tank for isolation before entering the electroplating unit, thereby removing impurity elements from the base film.

[0033] On the other hand, an electroplated conductive film generated based on the conductive film continuous coating equipment described above is provided. The conductive film has a surface-modifying component, which refers to a non-copper modified film layer on the surface of the copper layer during the thin film deposition process before the acid plating process, in order to improve the quality of the conductive film.

[0034] Alternatively, the microstructure of the conductive film coating can be adjusted to achieve overall film properties regulation.

[0035] The present invention has the following beneficial technical effects:

[0036] 1. The equipment structure of this invention is rationally designed, employing independent and spaced electroplating units. Each electroplating unit has an independent reagent circulation channel, and the base film continuously passes through adjacent electroplating units. This not only effectively achieves the electroplating operation but also allows for individual adjustment and control of localized copper ions in the reagents or the main salt copper ions, preventing component exchange between them. This improves the effectiveness of electroplating, enabling ultra-high-efficiency thin film deposition and enhancing the quality and effect of the coating. Different film layers with varying properties can be obtained through reagent combinations, solving the technical problems of low coating efficiency and the inability to individually control reagents in existing technologies. This invention achieves ultra-high-efficiency thin film deposition through individual reagent control, effectively ensuring precise or diversified control of the microstructure and properties of the coated film.

[0037] 2. The feed end in the base film transmission direction is equipped with a cleaning tank for removing impurities and for resin impurity removal and online monitoring. The cleaning tank is an acidic tank or an alkaline tank, which can remove impurities from the base film before electroplating, which is beneficial to improving the effect of subsequent electroplating. Moreover, it will not contaminate the chemicals in the electroplating unit, which is conducive to the recycling of chemicals and reduces electroplating costs.

[0038] 3. An isolation cleaning tank is provided between the impurity removal cleaning tank and the electroplating unit. The isolation cleaning tank is a water washing tank, which can clean the base film after impurity removal cleaning again, avoiding contamination of the chemicals in the electroplating unit by impurity elements in the impurity removal solution. This is conducive to the recycling of chemicals and reduces electroplating costs.

[0039] 4. The electroplating spacing in the electroplating unit at the rear end of the base film transmission direction is smaller than the electroplating spacing in the electroplating unit at the front end of the base film transmission direction. The smaller electroplating spacing and the larger current of the electroplating unit at this time can increase the electroplating current after the electroplating coating of the base film is increased by reducing the electroplating spacing, thereby improving the coating efficiency, increasing the film deposition rate, and increasing the film roughness. This meets the electroplating requirements of different situations and is also conducive to ensuring the efficiency and stability of electroplating, making it highly practical.

[0040] 5. Plating units with high copper ion concentration in the main salt can be arranged adjacently or non-adjacently with those with low copper ion concentration in the main salt. This can improve the flexibility of electroplating, meet the electroplating needs of different environments, and broaden its applicability.

[0041] 6. The electroplating method of the present invention is beneficial to improving the efficiency and effect of electroplating, increasing the film deposition rate, and allowing for the control of the surface roughness of the coated film layer to meet the electroplating requirements of films with different properties.

[0042] 7. By gradually increasing the thickness of the electroplating coating on the base film to complete the electroplating, impurities can be removed from the base film before electroplating, which is beneficial to improving the effect of subsequent electroplating. Moreover, it will not cause pollution to the chemicals in the electroplating unit, which is conducive to the recycling of chemicals and reduces electroplating costs.

[0043] 8. The present invention can achieve relatively convenient adjustment of the microstructure of the coating layer in each tank, thereby achieving the final adjustment of the physical properties of the overall coating layer. Attached Figure Description

[0044] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0045] Figure 1 This is a schematic diagram of the structure of the first embodiment of the present invention;

[0046] Figure 2 This is a schematic diagram of the structure of a second embodiment of the present invention;

[0047] Figure 3 This is a schematic diagram of the structure of a third embodiment of the present invention;

[0048] Figure 4 This is a schematic diagram illustrating multiple electroplating and coating units using different reagent systems according to an embodiment of the present invention;

[0049] Figure 5 This is a flowchart of the electroplating method according to an embodiment of the present invention.

[0050] Explanation of reference numerals in the attached figures:

[0051] 1. Electroplating unit; 11. Electroplating tank; 12. Transmission structure; 13. Electroplating reagent; 14. Lower electroplating anode; 15. Upper electroplating anode;

[0052] 2. Drug circulation channel;

[0053] 3. Base film;

[0054] 4. Impurity removal and cleaning tank;

[0055] 5. Isolation cleaning tank. Detailed Implementation

[0056] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0057] It should be noted that, in the absence of conflict, the following embodiments and features can be combined with each other; and, based on the embodiments of this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0058] It should be noted that various aspects of embodiments within the scope of the appended claims are described below. It will be apparent that the aspects described herein can be embodied in a wide variety of forms, and any particular structure and / or function described herein is merely illustrative. Based on this disclosure, those skilled in the art will understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects set forth herein can be used to implement the device and / or practice the method. Additionally, this device and / or method can be implemented using structures and / or functionalities other than one or more of the aspects set forth herein.

[0059] The present invention divides the existing integrated (same electroplating solution) production line structure into multiple independently operated and controlled electroplating units, thereby enabling better control of the microcrystalline structure and a significant increase in electroplating deposition efficiency, so as to achieve high-efficiency manufacturing of products with different performance characteristics.

[0060] The embodiments of the present invention construct an electroplating and coating functional system with at least two segments that can independently circulate electroplating agents, and implement the regulation of the stacked film structure and the improvement of ultra-high coating thickness efficiency to obtain a conductive film with a variety of regulated physical properties.

[0061] Compared to the traditional continuous coating equipment system with its overall large-scale chemical circulation design, the technical solution provided in this invention provides at least two independently controllable electroplating units with chemical circulation. Each independent electroplating unit is filled with electroplating chemicals of different formulations, and the two independent electroplating units can provide coating functions that are connected sequentially.

[0062] The electroplating agents in consecutive adjacent plating units have the following characteristics: firstly, the concentration of copper ions in the main salt of the later plating unit in the direction of the moving base film is significantly higher than that of the previous plating unit; secondly, the current tolerance of the agents in the later plating unit is higher than that of the previous plating unit.

[0063] Independent electroplating units are those where the plating agents are not substantially connected to each other to form a significant exchange of components; traditionally, each plating segment is a set of structures with an anode material; that is, multiple plating segments gradually thicken the copper layer during the plating process, so the agents of the entire plating line are a connected whole; in the embodiments of the present invention, the agents are separated from each other, and the agent components of the separated units can be different, and there is no exchange of components between them.

[0064] All the above types of equipment are characterized by the fact that as the thickness of the electroplating coating increases, the distance or spacing between the cathode and anode of each subsequent electroplating unit gradually shortens, which can increase the electroplating current and improve the coating efficiency.

[0065] During the coating process, the current tolerance of the reagents in the downstream electroplating unit is higher than that in the preceding electroplating unit 1, and / or, the unit area current density of the downstream electroplating unit is higher than that of the upstream electroplating unit. This is achieved through the high current tolerance of the reagents themselves and the adjustment of ion concentration to increase the unit area current density. The significantly higher unit area current density in this technical solution compared to the preceding electroplating unit means that, under traditional electroplating methods, when the entire production line uses the same electroplating reagents, the actual applied current density is higher for the unit thickness of the same incoming conductive film.

[0066] This invention also provides a conductive film product with surface-modifying components. The surface-modifying components refer to a non-copper modified film layer on the surface of the copper layer during the thin film deposition process before the acid plating process, which is used to improve the quality of the conductive film.

[0067] The aforementioned modified components refer to the deposition of other components on the outermost surface of the film layer in order to improve the quality of the film layer during the thin film deposition process preceding acid plating, which is different from the Cu layer film layer.

[0068] This invention also provides an adjustable microstructure for the coated conductive film layer, enabling the adjustment of the overall film properties. This is because increasing the film deposition rate can lead to increased film roughness. This invention allows for relatively convenient adjustment of the microstructure of the coated film layer in each tank, thereby achieving the final adjustment of the overall film properties.

[0069] Example 1

[0070] like Figure 1 As shown, a continuous conductive film coating apparatus includes at least two independent electroplating units 1. Each electroplating unit 1 is equipped with an independent reagent circulation channel 2 (which may include a Cu2+ source replenishment function). The base film 3 continuously passes through adjacent electroplating units 1, and the concentration of the main salt copper ions in the electroplating unit 1 at the rear end of the base film 3's transmission direction is higher than that in the electroplating unit 1 at the front end of the base film 3's transmission direction. Other components can be configured according to process requirements and are therefore not described in detail.

[0071] In this embodiment, the electroplating unit 1 includes an electroplating tank 11, a transmission structure 12 located in the electroplating tank 11 and used for driving the base film 3, an electroplating agent 13 located in the electroplating tank 11, a lower electroplating anode 14 and an upper electroplating anode 15 located in the electroplating tank 11; and its electroplating cathode and electroplating anode can be in a horizontal state, a V-shaped state or a vertical state, or a combination of horizontal and V-shaped. The electroplating agent 13 is connected to the circulation pump in the agent circulation channel 2.

[0072] In this embodiment, the transmission structure 12 includes conductive rollers, guide rollers, etc., mainly used to ensure the conductive film operates in a central position between the upper and lower anode functional modules, guaranteeing the effectiveness and stability of the transmission. An adjustable electroplating gap is provided between the lower electroplating anode 14 and the upper electroplating anode 15. A circulation pump is provided in the reagent circulation channel 2, mainly used to circulate the electroplating reagent 13, thereby ensuring the effective electroplating. The transmission structure 12, the lower electroplating anode 14, and the upper electroplating anode 15 are all existing technologies. In this embodiment, the distance of the electroplating gap can be adjusted to regulate the magnitude of the electroplating current. When the thickness of the base film 3 electroplating coating increases, the electroplating current needs to be increased to ensure the efficiency and effectiveness of the coating.

[0073] The electroplating unit 1 includes an electroplating tank 11, a transmission structure 12 located in the electroplating tank 11 and used for driving the base film 3, an electroplating agent 13 located in the electroplating tank 11, and a lower electroplating anode 14 and an upper electroplating anode 15 located in the electroplating tank 11.

[0074] When copper thin film deposition is assisted by insoluble anode plates, two insoluble anode plates are provided in the electroplating tank 11, serving as the lower electroplating anode 14 and the upper electroplating anode 15, respectively; the base film 3 serves as the cathode, used to accept copper ions and reduce them to form a copper film deposition.

[0075] When copper ions are provided by dissolving copper phosphate balls, the electroplating tank 11 is equipped with a lower copper phosphate ball and an upper copper phosphate ball, which serve as the lower electroplating anode 14 and the upper electroplating anode 15, respectively. The regulation of the main salt copper ions in each electroplating tank 11 is achieved by one of the following methods: dissolving the copper phosphate balls themselves; supplying external copper ions; or combining the dissolution of copper phosphate balls with the supply of external copper ions.

[0076] The electroplating agent 13 is connected to the circulation pump in the agent circulation channel 2; an adjustable electroplating gap is provided between the lower electroplating anode 14 and the upper electroplating anode 15.

[0077] This embodiment employs two methods: First, insoluble anode plates are used to assist in the deposition of Cu thin films. In this process, insoluble anode plates, such as 14 and 15, are the upper and lower anode plates, respectively. The base film 3 is a cathode deposition that accepts Cu2+, which is then reduced to obtain the Cu film deposition. Second, copper-phosphorus balls are dissolved to provide a Cu2+ source for deposition. As shown in the figure, 14 and 15 are copper-phosphorus balls. Finally, the control of the main salt Cu2+ in each tank is achieved by the copper-phosphorus balls themselves, an external Cu2+ source, or copper-phosphorus balls plus an external Cu2+ source.

[0078] In practical applications, the electroplating spacing in the electroplating unit 1 at the rear end of the base film 3 in the transmission direction is smaller than the electroplating spacing in the electroplating unit 1 at the front end of the base film 3 in the transmission direction; the distance is 5cm to 15cm, and when the electroplating spacing is small, the current of the electroplating unit 1 is large.

[0079] In this embodiment, the electroplating unit 1 with a high concentration of copper ions in the main salt is arranged adjacently or non-adjacently to the electroplating unit 1 with a low concentration of copper ions in the main salt. This arrangement improves the flexibility and convenience of electroplating, meeting the needs of different situations. The formulation of the electroplating agent 13 contained in each electroplating unit 1 is different.

[0080] In this embodiment, the reagent circulation channel 2 is also used to replenish copper ions into the correspondingly connected electroplating unit 1. The reagent circulation channel 2 includes a Cu2+ source replenishment function; it not only circulates the electroplating solution but also automatically replenishes Cu2+ (copper ions). During the electroplating process, Cu2+ in the solution is continuously consumed, therefore this function is crucial for maintaining electroplating efficiency and coating quality. By continuously replenishing Cu2+, the system can maintain a stable concentration of copper ions in the solution, thereby ensuring the continuity and consistency of the electroplating process.

[0081] The Cu2+ source replenishment function plays a crucial role in the electroplating process. During electroplating, Cu2+ in the solution is continuously consumed and deposited onto the surface of the object being plated. To maintain electroplating efficiency and coating quality, it is necessary to continuously maintain the concentration of Cu2+ in the solution.

[0082] There are several ways to achieve this functionality. One method is to place a copper anode in the circulation channel, which gradually dissolves during the electroplating process, releasing Cu2+ into the solution. Another method is to equip the system with an automatic device for adding concentrated copper salt solution, replenishing Cu2+ as needed. Alternatively, a sensor monitoring Cu2+ concentration can be used, automatically triggering a replenishment mechanism when the concentration decreases. All these methods effectively maintain the Cu2+ concentration balance in the solution.

[0083] The Cu2+ source replenishment function offers several advantages. First, this design enables continuous electroplating, reducing downtime caused by insufficient Cu2+ concentration and improving production efficiency. Second, it helps maintain the stability of the electroplating solution, thereby improving the consistency of coating quality and ensuring product quality. Finally, this automated replenishment mechanism simplifies the operation process, reduces the need for manual intervention, and lowers operating costs and the possibility of human error.

[0084] Specifically, the drug circulation channel 2 may include:

[0085] A circulation pipeline connected to the electroplating tank 11 in the corresponding electroplating unit 1 is used for circulating the electroplating solution; and at least one of the following two copper ion replenishment devices: the first copper ion replenishment device is a copper anode installed in the circulation pipeline for releasing copper ions into the solution; the second copper ion replenishment device specifically includes: a concentrated copper salt solution storage tank connected to the circulation pipeline, and a metering pump installed at the connection between the storage tank and the circulation pipeline for controlling the addition of concentrated copper salt solution; a copper ion concentration sensor installed on the circulation pipeline for monitoring the concentration of copper ions in the solution; and a control unit electrically connected to the copper ion concentration sensor and the metering pump for controlling the start / stop or corresponding operating state of the metering pump based on the monitoring data of the copper ion concentration sensor.

[0086] The embodiments of the present invention have the following beneficial technical effects:

[0087] 1. The equipment structure of this invention is reasonably designed, employing independent electroplating units 1. Each electroplating unit 1 is equipped with an independent reagent circulation channel 2, and the base film 3 continuously passes through adjacent electroplating units 1. This not only effectively realizes the electroplating operation, but also allows for individual adjustment and control of local copper ions in the reagent, preventing component exchange between them. This improves the effectiveness of electroplating, enabling ultra-high efficiency thin film deposition, enhancing the quality and effect of the coating, and allowing for the creation of films with different properties through reagent combination. This solves the technical problems of low coating efficiency and inability to individually control reagents in the prior art.

[0088] 2. The electroplating spacing in the electroplating unit 1 at the rear end of the base film 3 in the transmission direction is smaller than the electroplating spacing in the electroplating unit 1 at the front end of the base film 3 in the transmission direction. The electroplating spacing is small and the current of the electroplating unit 1 is large at this time. After the electroplating coating of the base film 3 is increased, the electroplating spacing can be reduced to increase the current of electroplating, thereby improving the coating efficiency, increasing the film deposition rate, and increasing the roughness of the film. This meets the electroplating requirements of different situations and is also conducive to ensuring the efficiency and stability of electroplating.

[0089] 3. Plating unit 1 with high main salt copper ion concentration can be arranged adjacently or non-adjacently with plating unit 1 with low main salt copper ion concentration, which can improve the flexibility of electroplating, meet the electroplating needs of different environments, and expand its applicability.

[0090] 4. Independent cyclic control of each electroplating unit is possible, allowing for the application of different process techniques to each reagent (e.g., different copper ion concentrations in separate sections, 120g / L, 150g / L, 180g / L), ultimately resulting in films with different properties through reagent combination. Maintaining a copper ion concentration within a certain range also facilitates the implementation of corresponding modulation or control methods for the copper ion concentration.

[0091] 5. Based on the reagent with independent control unit, combined with the different current tolerance of the reagent, the ultra-high current control mode is implemented compared with the traditional reagent (it can increase the current in a way that is close to the cost, or at least 30% more than the traditional electroplating coating with the increase of current as the thickness changes), which greatly improves the efficiency of film deposition, shortens the electroplating coating production line, and saves investment.

[0092] 6. The reagents in a single cycle can not only deposit films with different physical properties, but also, combined with the optimized design of the stacked structure, ultimately obtain conductive film products with a variety of unique properties.

[0093] Example 2

[0094] like Figure 2 As shown, this embodiment is basically the same as embodiment 1, except that: the feed end of the base film 3 in the transmission direction is provided with a cleaning tank 4 for removing impurity elements (e.g., resin impurity removal) and can be monitored online; it removes impurities with resin and is equipped with an online monitoring system, which can adjust the impurity removal within a certain range to improve the effectiveness and reliability of impurity removal. The cleaning tank 4 is located in front of the electroplating unit 1 at the foremost end of the base film 3 in the transmission direction.

[0095] Specifically, the impurity removal cleaning tank 4 can be an acidic tank or an alkaline tank. To address the undesirable impurity elements that may be introduced into the surface-modified coating due to film defects, an acid or alkaline cleaning tank is set up upstream or at the front end of the formal electroplating unit to remove or partially remove the impurity elements, thereby preventing the surface-modified material from contaminating the reagents in the subsequent formal electroplating unit.

[0096] In alternative embodiments, the cleaning tank 4 may be omitted or omitted. Although there may be some degree of contamination, the objectives of the embodiments of the present invention can still be achieved.

[0097] The advantages of this embodiment of the invention are as follows: the feed end of the base film 3 in the transmission direction is provided with a cleaning tank 4 for removing impurity elements and for resin impurity removal and online monitoring. The cleaning tank 4 is an acidic tank or an alkaline tank, which can remove impurity elements from the base film 3 before electroplating, which is beneficial to improving the effect of subsequent electroplating. Moreover, it will not cause pollution to the reagents in the electroplating unit 1, which is conducive to the recycling of reagents and reduces electroplating costs.

[0098] In some optional embodiments, online monitoring is implemented as follows:

[0099] The base film 3 is provided with a cleaning tank 4 at the feed end in the transmission direction for removing impurity elements and for online monitoring; the cleaning tank 4 is located in front of the electroplating unit 1 at the foremost point in the transmission direction of the base film 3; the cleaning tank 4 is equipped with a real-time online monitoring system for monitoring the cleaning process and cleaning effect.

[0100] Example 3

[0101] like Figure 3 As shown, this embodiment is basically the same as embodiment 2, except that an isolation cleaning tank 5 is provided between the impurity removal cleaning tank 4 and the electroplating unit 1. The isolation cleaning tank 5 can be a water washing tank.

[0102] The advantage of this embodiment of the invention is that an isolation cleaning tank 5 is provided between the impurity removal cleaning tank 4 and the electroplating unit 1. The isolation cleaning tank is a water washing tank, which can clean the base film 3 after impurity removal cleaning again, avoiding the contamination of the reagents in the electroplating unit 1 by impurity elements in the impurity removal solution. This is conducive to the recycling of reagents and reduces electroplating costs.

[0103] Example 4

[0104] In this embodiment, the electroplating spacing in the electroplating unit 1 at the rear end of the base film 3 in the transmission direction is smaller than the electroplating spacing in the electroplating unit 1 at the front end of the base film 3 in the transmission direction; the smaller the electroplating spacing, the larger the current of the corresponding electroplating unit 1.

[0105] The electroplating agent 13 in the rear electroplating unit 1 has a higher current tolerance than the electroplating agent 13 in the previous electroplating unit 1, and / or the current density per unit area of ​​the rear electroplating unit 1 is higher than that of the front electroplating unit 1.

[0106] The electroplating unit 1 with a high concentration of copper ions in the main salt is arranged adjacently or non-adjacently to the electroplating unit 1 with a low concentration of copper ions in the main salt; the reagent circulation channel 2 is also used to replenish copper ions in the corresponding connected electroplating unit 1.

[0107] When the distance between the base film 3 and the lower electroplating anode 14 and the upper electroplating anode 15 remains constant, the concentration of copper ions in the main salt increases along the transmission direction of the base film 3; and / or, when the distance between the base film 3 and the lower electroplating anode 14 and the upper electroplating anode 15 decreases with the transmission direction of the base film 3, the concentration of copper ions in the main salt increases.

[0108] Specifically, the following is a detailed analysis of the effects of cathode-anode distance, copper ion concentration, and current density on deposition efficiency and microcrystalline structure (here only the effect on deposition rate is considered):

[0109] With the distance between the cathode and anode remaining constant, increasing the copper ion concentration is beneficial for increasing the deposition rate. In this case, increased conductivity leads to increased current; furthermore, increasing the voltage on this basis will further increase the current, thus allowing the deposition rate to increase even faster.

[0110] When the distance between the cathode and anode decreases (of course, depending on the adjustment of the microstructure in this embodiment, the distance may also increase, which can be modulated by the concentration of copper ions), the above-mentioned treatment when the distance between the cathode and anode remains unchanged can be superimposed.

[0111] Specifically, the deposition rate increases when the distance between the cathode and anode decreases. When the distance between the cathode and anode is smaller, the resistance in the solution is relatively low. According to Ohm's law, under the same voltage, the current will be relatively large, allowing more copper ions to gain electrons at the cathode surface and be reduced to copper atoms, thus accelerating the deposition rate of the copper thin film.

[0112] Specifically, when the distance between the cathode and anode is too large, the deposition rate slows down. When the distance between the cathode and anode is too large, the solution resistance increases, the resistance to current flow is enhanced, leading to a decrease in current density. This reduces the number of copper ions that can reach the cathode surface, thus slowing down the deposition rate of the copper film. Furthermore, an excessive distance weakens the electric field strength, reducing the driving force for copper ions to migrate towards the cathode under the influence of the electric field, which is also detrimental to the rapid deposition of copper ions.

[0113] Specifically, as the concentration of copper ions increases, the deposition rate accelerates. Within a certain range, an increase in the concentration of copper ions in the plating solution increases the number of copper ions available for reduction and deposition per unit volume. This increases the probability that copper ions on the cathode surface can come into contact with and gain electrons to be reduced, thereby accelerating the deposition rate of the copper thin film.

[0114] Specifically, excessively high copper ion concentrations limit the deposition rate. Once the copper ion concentration exceeds a certain limit, further increases in concentration will gradually reduce the effect on improving the deposition rate. This is because excessively high copper ion concentrations lead to increased viscosity of the plating solution and slower diffusion rates, affecting the diffusion and mass transfer process of copper ions to the cathode surface. Consequently, the copper ion concentration near the cathode surface cannot be replenished in time, thus limiting further increases in the deposition rate.

[0115] Specifically, if the copper ion concentration is too low, the deposition rate slows down. When the copper ion concentration is too low, the number of copper ions available on the cathode surface is limited, which cannot meet the requirements for rapid deposition, resulting in a slower deposition rate. Moreover, an excessively low concentration also reduces the conductivity of the plating solution, affecting the current transmission in the plating solution, and thus indirectly affecting the deposition rate of the copper thin film.

[0116] Specifically, increasing the current density accelerates the deposition rate. Current density refers to the amount of current passing through a unit area of ​​the cathode. When the current density increases, the electron supply to the cathode surface is more abundant, attracting more copper ions to gain electrons and be reduced to copper atoms, thus significantly increasing the deposition rate of the copper film. According to Faraday's law, the amount of electricity passing through the electrode is directly proportional to the amount of substance undergoing a chemical reaction at the electrode. Therefore, under otherwise constant conditions, the higher the current density, the more copper is deposited per unit time, and the faster the deposition rate.

[0117] Specifically, excessive current density leads to a decrease in deposition quality. If the current density exceeds the range allowed by the plating solution and process, it will cause intensified cathode polarization, resulting in an excessively rapid reduction rate of copper ions on the cathode surface. This easily leads to the formation of a rough, loose, or even dendritic coating. Such a coating not only has poor appearance quality but also weak adhesion, making it prone to peeling and flaking. It may also be accompanied by a large amount of hydrogen evolution, further affecting the coating quality and deposition rate.

[0118] Specifically, if the current density is too low, the deposition efficiency decreases. When the current density is too low, the number of electrons obtained by the cathode surface is limited, the reduction rate of copper ions is slow, and the deposition rate of copper thin film will naturally be slower, resulting in low production efficiency and failing to meet the needs of large-scale production.

[0119] Specifically, according to Ohm's law, in an electroplating apparatus, when the distance between the cathode and anode remains constant, the resistance of the electrolyte remains essentially constant. As the copper ion concentration increases, the conductivity of the electrolyte increases. Conductivity is the reciprocal of resistivity; an increase in conductivity results in a decrease in resistance (assuming a constant electrode distance). Assuming the external power supply voltage of the electroplating apparatus remains constant, according to Ohm's law, due to the decrease in resistance, the current will increase.

[0120] Specifically, from the perspective of ion migration, with a constant electrode area, an increase in current leads to an increase in current density. When the copper ion concentration increases, the number of copper ions migrating to the cathode surface per unit time increases under the influence of the electric field, thus accelerating the reaction rate at the cathode surface. To maintain charge balance, more electrons flow from the anode to the cathode through the external circuit, resulting in an increase in current and, consequently, current density. Therefore, in electroplating equipment, an increase in copper ion concentration, with a constant distance between the cathode and anode, will lead to an increase in current density.

[0121] Example 5

[0122] In this embodiment, adjacent electroplating units can use the same reagent system or different reagent systems. Different reagent systems have their own advantages in microstructure control. Furthermore, if adjacent electroplating units use different reagent systems, an isolation and cleaning device can be further implemented to prevent cross-contamination.

[0123] The following section details solutions to the types of chemical systems used in electroplating units and the issues of isolation and contamination prevention between adjacent chemical systems.

[0124] The electroplating agents in different electroplating units can be from different agent systems (all electroplating units can use the same system, or multiple agent systems can be used). Along the direction of substrate film transfer, the concentration of copper ions (the main salt) in the same agent system gradually increases. For different agent systems, the concentration along the substrate film transfer direction is not limited (i.e., subsequent units with different agent systems can have lower copper ion concentrations than previous units). A single coating production line can use multiple agent systems to form a line that meets the actual coating requirements. The processes between different agent systems can be continuous or discontinuous.

[0125] like Figure 4 As shown, in Figure 4In the example above, electroplating units 1, 2, 3, and 4 are arranged continuously at intervals along the transmission direction of the base film. Electroplating units 1 and 2 use reagent system 1, electroplating unit 3 uses reagent system 2, and electroplating unit 4 uses reagent system 3. The copper ion concentrations in electroplating units 1, 2, 3, and 4 are 100 g / L, 120 g / L, 100 g / L, and 100 g / L, respectively; or 100 g / L, 120 g / L, 125 g / L, and 135 g / L.

[0126] like Figure 4 As shown, in Figure 4 In one example below, electroplating units 1, 2, 3, 4, and 5 are arranged continuously at intervals along the transmission direction of the base film. The reagent systems for electroplating units 1, 2, 3, 4, and 5 are: reagent system 1, reagent system 2, reagent system 3, reagent system 1, and reagent system 2, respectively. The copper ion concentrations for electroplating units 1, 2, 3, 4, and 5 are: 100 g / L, 100 g / L, 100 g / L, 120 g / L, and 125 g / L, respectively.

[0127] Specifically, the reagents in the above-mentioned different systems may include: acidic copper sulfate system, pyrophosphate copper plating system, cyanide copper plating system, and alkaline cyanide-free copper plating system.

[0128] The acidic copper sulfate system mainly consists of copper sulfate (CuSO4) and sulfuric acid (H2SO4). Copper sulfate provides copper ions (Cu... 2+ The concentration of acidic copper sulfate is generally between 150-250 g / L. Sulfuric acid can increase the conductivity of the solution and help improve the quality of copper deposition, with a concentration of around 50-100 g / L. This system has advantages such as high conductivity, simple composition, and low cost. Acidic copper sulfate systems are widely used in the electroplating copper process of printed circuit boards (PCBs). In PCB manufacturing, acidic copper sulfate electroplating can form a uniform copper film on the hole walls and circuit surfaces, ensuring good conductivity and reliability of the circuit board. For example, in the fabrication of inner layer circuits in multilayer PCBs, acidic copper sulfate electroplating is used to thicken the copper layer of the circuits to meet the requirements of subsequent processing and use.

[0129] The pyrophosphate copper plating system primarily consists of copper pyrophosphate (Cu₂P₂O₇) and potassium pyrophosphate (K₄P₂O₇). Copper pyrophosphate acts as the copper ion source, while potassium pyrophosphate serves as a complexing agent, forming stable complexes with copper ions. This plating solution exhibits excellent dispersibility and fine crystallization, enabling the formation of uniform copper plating on complex-shaped workpieces. Its pH value is typically controlled between 8 and 9, and the operating temperature is between 30 and 50°C. The pyrophosphate copper plating system is suitable for electroplating copper onto complex-shaped metal products, such as various precision mechanical parts and decorative items. For instance, for small mechanical parts with complex internal cavities, the pyrophosphate copper plating system allows for uniform copper deposition on all surfaces, including hard-to-reach internal cavities, thereby improving the corrosion resistance and appearance quality of the parts.

[0130] The main components of cyanide copper plating systems are cuprous cyanide (CuCN) and sodium cyanide (NaCN). Sodium cyanide acts as both a complexing agent for copper ions and an important component for maintaining solution stability. This plating system exhibits excellent homogenization and coverage capabilities, enabling the formation of copper plating layers with strong adhesion on various substrate materials. However, due to the high toxicity of cyanide, this system poses significant safety and environmental risks. Cyanide copper plating systems still find applications in some special situations where extremely high adhesion is required. For example, when electroplating copper onto steel substrates, cyanide copper plating can serve as an undercoat, providing a good bonding base for subsequent electroplating of other metals and preventing plating peeling. However, due to its toxicity, strict adherence to safety operating procedures and effective wastewater treatment measures are necessary during its use.

[0131] Alkaline cyanide-free copper plating systems are environmentally friendly electroplating solutions developed to replace cyanide copper plating. Common examples include copper plating solutions using organophosphonates or ethylenediaminetetraacetate (EDTA) as complexing agents. These systems offer the advantages of being cyanide-free and environmentally friendly, while also ensuring relatively good electroplating results, such as good coverage and moderate deposition rates. With increasingly stringent environmental requirements, alkaline cyanide-free copper plating systems are finding wider application in many industries, such as automotive parts and hardware / sanitary ware electroplating, reducing harm to the environment and operator health while ensuring product quality.

[0132] Specifically, in order to solve the problem of preventing contamination of different chemical systems, this embodiment sets up an anti-contamination isolation device between electroplating and coating units. The anti-contamination isolation device is set up with symmetrical air knives at the top and bottom. The air knives are parallel to the base film and perpendicular to the transmission direction of the base film, or form a certain angle, and the acute angle of the angle is not less than 30°.

[0133] Furthermore, the air outlet of the air knife faces the opposite direction of the base film transmission direction. This opposite direction means that the air velocity at the air outlet, in terms of the transmission direction perpendicular or parallel to the base film, has at least a velocity component opposite to the base film transmission direction.

[0134] Example 6

[0135] like Figure 5 As shown, a continuous conductive film deposition method includes the following steps:

[0136] Step A: Real-time detection of the main salt copper ion concentration in the electroplating unit 1 at the rear end of the base film 3 in the transmission direction and the main salt copper ion concentration in the electroplating unit 1 at the front end of the base film 3 in the transmission direction, and ensuring that the main salt copper ion concentration in the electroplating unit 1 at the rear end is greater than the main salt copper ion concentration in the electroplating unit 1 at the front end.

[0137] Step B: The base film 3 is continuously passed through the electroplating unit 1 with a low concentration of copper ions in the main salt and the electroplating unit 1 with a high concentration of copper ions in the main salt in the self-transmission direction.

[0138] Step C: Gradually increase the thickness of the electroplated coating on the base film 3 to complete the electroplating.

[0139] Furthermore, between step B and step C, the following step may also be included: Step C, adjusting the electroplating spacing between the electroplating cathode and electroplating anode in different electroplating units 1, so as to increase the electroplating current in the electroplating unit 1 with a high concentration of main salt copper ions.

[0140] In this embodiment, the electroplating spacing can range from 5 to 15 cm. The mesh area of ​​the anode plate corresponds to a smaller distance, and the plate-like area of ​​the anode plate corresponds to a larger distance. This is mainly because the difference in the necessary copper ion concentration transport and distribution is smaller. That is, the electroplating anode includes an anode plate, which is disposed within the electroplating unit; the anode plate includes a mesh area and a plate-like area; the electroplating spacing between the anode plate and the electroplating cathode ranges from 5 to 15 cm; the first electroplating spacing between the mesh area and the electroplating cathode is smaller than the second electroplating spacing between the plate-like area and the electroplating cathode.

[0141] Specifically, the term "small distance" in the context of anode plate mesh regions refers to the design of mesh structures in certain areas of the anode plate. These mesh regions are located relatively close to the cathode. The mesh structure increases the surface area, which is beneficial for the release of copper ions and the flow of the solution. The smaller distance indicates a shorter transport path for copper ions from the anode to the cathode, contributing to improved electroplating efficiency.

[0142] Specifically, the large distance corresponding to the plate-like region of the anode plate means that other areas of the anode plate maintain a plate-like structure, and these plate-like regions are relatively far from the cathode. The plate-like regions provide a stable copper source, while the larger distance helps to control the current density and deposition rate.

[0143] The main purpose of this design is to optimize the transport and distribution of copper ions. By combining mesh and plate structures, and adjusting the plating spacing in different areas, the following effects can be achieved: ensuring that copper ions can be effectively transported from the anode to the cathode; making the distribution of copper ion concentration in the plating solution more uniform and reducing local concentration differences; balancing the needs of rapid plating (mesh area) and stable supply (plate area); and ultimately, maintaining a more consistent and controllable copper ion concentration throughout the plating process, thereby improving plating quality and uniformity.

[0144] Furthermore, in practical applications, in step D, the base film 3 passes through the impurity removal cleaning tank 4 and the isolation cleaning tank 5 in sequence before entering the electroplating unit 1, thereby removing impurity elements from the base film 3.

[0145] The electroplating method of this invention improves electroplating efficiency and effect, increases film deposition rate, and allows for control of the surface roughness of the coated film, meeting the electroplating requirements of films with different properties. The electroplating method of this invention gradually increases the thickness of the electroplated coating on the base film to complete the electroplating process. It allows for the removal of impurities from the base film before electroplating, which improves the effect of subsequent electroplating. Furthermore, it avoids contaminating the chemicals within the electroplating unit, facilitating chemical recycling and reducing electroplating costs.

[0146] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A continuous conductive film coating apparatus, characterized in that: It includes at least two independent electroplating units (1), each of which is provided with an independent reagent circulation channel (2); The base film (3) passes through adjacent electroplating units (1) in succession, and the concentration of copper ions in the main salt in the electroplating unit (1) at the rear end of the base film (3) in the transmission direction is higher than the concentration of copper ions in the electroplating unit (1) at the front end of the base film (3) in the transmission direction.

2. The conductive film continuous coating equipment according to claim 1, characterized in that: The electroplating unit (1) includes an electroplating tank (11), a transmission structure (12) located in the electroplating tank (11) and used for the transmission of the base film (3), an electroplating agent (13) located in the electroplating tank (11), and a lower electroplating anode (14) and an upper electroplating anode (15) located in the electroplating tank (11). The electroplating agent (13) is connected to the circulation pump in the agent circulation channel (2); An adjustable electroplating gap is provided between the lower electroplating anode (14) and the upper electroplating anode (15).

3. The conductive film continuous coating equipment according to claim 2, characterized in that: The electroplating spacing in the electroplating unit (1) at the rear end of the base film (3) in the transmission direction is smaller than the electroplating spacing in the electroplating unit (1) at the front end of the base film (3) in the transmission direction. The smaller the electroplating spacing, the greater the current of the corresponding electroplating unit (1).

4. The conductive film continuous coating equipment according to claim 3, characterized in that: The electroplating agent (13) in the rear electroplating unit (1) has a higher current tolerance than the electroplating agent (13) in the previous electroplating unit (1), and / or, the current density per unit area of ​​the rear electroplating unit (1) is higher than that of the front electroplating unit (1).

5. The conductive film continuous coating equipment according to claim 1, characterized in that: The electroplating unit (1) with a high concentration of copper ions in the main salt is arranged adjacent to or not adjacent to the electroplating unit (1) with a low concentration of copper ions in the main salt; the reagent circulation channel (2) is also used to replenish copper ions in the corresponding connected electroplating unit (1); When the distance between the base film (3) and the lower electroplating anode (14) and the upper electroplating anode (15) remains constant, the concentration of copper ions in the main salt increases along the transmission direction of the base film (3); and / or, When the distance between the base film (3) and the lower electroplating anode (14) and the upper electroplating anode (15) decreases with the transmission direction of the base film (3), the concentration of copper ions in the main salt increases.

6. The conductive film continuous coating equipment according to claim 1, characterized in that: The formulation of the electroplating agent (13) contained in each electroplating unit (1) is different; and / or, In each electroplating unit, adjacent electroplating units may use the same reagent system or different reagent systems; When the same reagent system is used, the same reagent system is selected from any one of the following: acidic copper sulfate system, pyrophosphate copper plating system, cyanide copper plating system, and alkaline cyanide-free copper plating system. When different reagent systems are used, the different reagent systems are selected from any combination of the following: acidic copper sulfate system, pyrophosphate copper plating system, cyanide copper plating system, and alkaline cyanide-free copper plating system.

7. The conductive film continuous coating equipment according to claim 1, characterized in that: The base film (3) is provided with a cleaning tank (4) for removing impurity elements and for online monitoring at the feed end in the transmission direction; The impurity removal cleaning tank (4) is located in front of the electroplating unit (1) at the foremost point of the base film (3) in the transmission direction.

8. The conductive film continuous coating equipment according to claim 7, characterized in that: An isolation cleaning tank (5) is provided between the impurity removal cleaning tank (4) and the electroplating unit (1).

9. A conductive film continuous coating apparatus according to claim 7 or claim 8, characterized in that: The impurity removal cleaning tank (4) is an acidic tank or an alkaline tank; the isolation cleaning tank (5) is a water washing tank.

10. A method for continuous deposition of a conductive film, characterized in that: Includes the following steps: Step A: Real-time detection of the concentration of copper ions in the main salt in the electroplating unit (1) at the rear end of the base film (3) in the transmission direction and the concentration of copper ions in the main salt in the electroplating unit (1) at the front end of the base film (3) in the transmission direction, and make the concentration of copper ions in the main salt in the electroplating unit (1) at the rear end greater than the concentration of copper ions in the electroplating unit (1) at the front end. Step B: The base film (3) is continuously passed from the transmission direction through the electroplating unit (1) with low main salt copper ion concentration and the electroplating unit (1) with high main salt copper ion concentration. Step C: Gradually increase the thickness of the electroplating coating on the base film (3) to complete the electroplating.

11. An electroplated conductive film generated using the conductive film continuous coating equipment according to any one of claims 1-9, characterized in that, The conductive film has a surface-modifying component, which refers to a non-copper modified film layer on the surface of the copper layer during the thin film deposition process before the acid plating process. Alternatively, the microstructure of the conductive film coating can be adjusted to achieve regulation of the overall physical properties of the film.

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