Electroplating method for circuit board and circuit board

Abstract

The present application relates to the technical field of circuit boards, and specifically discloses a method for electroplating a circuit board and a circuit board, wherein the method comprises: performing preliminary treatment on the circuit board to be electroplated to form a blind hole on one side of the circuit board; electroplating the circuit board after the preliminary treatment once using a plating solution and an additive; wherein the plating solution comprises a plating solution and an accelerator; electrolyzing the circuit board after the primary electroplating once to remove the accelerator adsorbed on one side of the circuit board after the electroplating, and retaining the accelerator adsorbed on the bottom and part of the side wall of the blind hole; and electroplating the circuit board after the primary electrolysis treatment a second time. In this way, the method for electroplating a circuit board in the present application can effectively improve the efficiency of electroplating hole filling, thereby shortening the hole filling time, and can effectively fill the blind holes of the circuit board.

Description

Technical Field

[0001] The present application relates to the technical field of circuit boards, and in particular to a method for electroplating a circuit board and a circuit board. Background Art

[0002] Nowadays, with the continuous development of PCB (Printed Circuit Board) in the industry, the requirements for PCB manufacturing technology and its quality are gradually increasing.

[0003] Regarding the copper plating process for filling holes on circuit boards, direct current or pulse current is generally used for electroplating. The waveform of the pulse current usually has the following characteristics: (1) The forward current density is close to the current density during direct current plating; (2) The reverse current density is greater than the forward current density; (3) The reverse current duration is less than the forward current duration, and the ratio of the reverse current to the forward current duration is between 1:5 and 1:100, with 1:20 being the most common. (4) The forward and reverse pulse durations are very short, with the reverse pulse duration generally being less than 20μs, with 1-5μs being the most common.

[0004] However, in actual production, the aspect ratio (hole depth: hole diameter) of blind vias in circuit boards is generally controlled at a specification of less than 0.8:1. In particular, the hole depth of blind vias that require filling rarely exceeds 120μm. As a result, during the hole filling electroplating process, especially the hole filling electroplating process of deep blind vias with a hole depth greater than 120μm, problems such as low hole filling efficiency, excessively long filling time, and incomplete filling of the blind vias are unavoidable. Summary of the Invention

[0005] The present application provides a circuit board electroplating method and a circuit board to solve the problems of low hole filling efficiency, long time, and incomplete filling of blind holes in the circuit board electroplating method in the prior art.

[0006] In order to solve the above technical problems, a technical solution adopted in the present application is: to provide a method for electroplating a circuit board, wherein the method for electroplating a circuit board includes: performing preliminary treatment on the circuit board to be electroplated to form a blind hole on one side of the circuit board; electroplating the circuit board after the preliminary treatment once using an electroplating solution and an additive; wherein the additive includes an accelerator; electrolyzing the circuit board after the primary electroplating once to remove the accelerator adsorbed on one side of the circuit board after the primary electroplating, and retaining the accelerator adsorbed on the bottom and part of the side wall of the blind hole; and electroplating the circuit board after the primary electrolysis treatment for a secondary time.

[0007] Among them, after the step of performing a primary electrolysis on the circuit board after the primary electroplating to remove the accelerator adsorbed on one side of the circuit board after the primary electroplating and retaining the accelerator adsorbed on the bottom and part of the side wall of the blind hole, and before the step of performing a secondary electroplating on the circuit board after the primary electrolysis treatment: the step of performing a primary electroplating on the circuit board after the primary treatment using the electroplating solution and the additive and the step of performing a primary electrolysis on the circuit board after the primary electroplating to remove the accelerator adsorbed on one side of the circuit board after the electroplating and retaining the accelerator adsorbed on the bottom and part of the side wall of the blind hole are repeated at least once.

[0008] The step of electroplating the preliminarily treated circuit board once with the electroplating solution and the additive includes: electroplating the preliminarily treated circuit board once with the electroplating solution in forced convection.

[0009] The step of electroplating the preliminarily treated circuit board once using the electroplating solution and the additive includes: performing a single electroplating treatment on the preliminarily treated circuit board using the electroplating solution for a duration of 5-60 minutes.

[0010] The step of performing a first electrolysis on the circuit board after the first electroplating includes: performing a first electrolysis treatment on the circuit board after the first electroplating for a duration of 5-120 seconds.

[0011] Among them, the step of electroplating the circuit board after the preliminary treatment with the electroplating solution and the additive includes: using a first DC power supply and electroplating the circuit board after the preliminary treatment with the electroplating solution and the additive; the step of electrolyzing the circuit board after the primary electroplating includes: using a second DC power supply and electrolyzing the circuit board after the primary electroplating; wherein the current density outputted to the circuit board by the first DC power supply is greater than the current density outputted to the circuit board by the second DC power supply.

[0012] The step of electrolyzing the plated circuit board includes: electrolyzing the plated circuit board using an electrolytic solution; wherein the electrolytic solution is different from the electroplating solution.

[0013] The electrolytic solution includes acid ions.

[0014] The electroplating solutions used in each of the two electroplating processes are different.

[0015] In order to solve the above technical problems, another technical solution adopted in the present application is: to provide a circuit board, wherein the circuit board is obtained by the electroplating method of the circuit board as described in any of the above items.

[0016] The beneficial effect of the present application is that, unlike the prior art, the circuit board electroplating method of the present application forms a blind hole on one side of the circuit board, and after electroplating the circuit board after the preliminary treatment with a plating solution and an additive, the accelerator adsorbed on one side of the circuit board after the electroplating can be removed by electrolyzing the circuit board after the first electroplating, and the accelerator adsorbed on the bottom and part of the side wall of the blind hole can be retained, thereby enhancing the effect of the specific adsorption of the additive, ensuring that the secondary electroplating of the circuit board after the first electrolysis treatment can quickly fill the blind hole of the circuit board, so as to effectively improve the efficiency of electroplating hole filling and shorten the hole filling time. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without inventive efforts. Among them:

[0018] Figure 1a This is a schematic flow chart of a first embodiment of the electroplating method for a circuit board of the present application;

[0019] Figure 1b-1f yes Figure 1a A schematic structural diagram of an embodiment corresponding to S11-S14;

[0020] Figure 1g This is a side view of an electroplating tank and an electrolytic tank used in a specific application scenario of the circuit board electroplating method of the present application;

[0021] Figure 1h yes Figure 1g A top view of a specific embodiment of the electroplating tank and the electrolytic tank;

[0022] Figure 1i yes Figure 1g A top view of another specific embodiment of the electroplating tank and the electrolytic tank;

[0023] Figure 1j yes Figure 1g A top view of another specific embodiment of the electroplating tank and the electrolytic tank;

[0024] Figure 1k This is a side view of an electroplating tank and an electrolytic tank used in another specific application scenario of the circuit board electroplating method of the present application;

[0025] Figure 11 yes Figure 1k A top view of a specific embodiment of the electroplating tank and the electrolytic tank;

[0026] Figure 1myes Figure 1k A top view of another specific embodiment of the electroplating tank and the electrolytic tank;

[0027] Figure 2 It is a flow chart of the second embodiment of the electroplating method for a circuit board of the present application. DETAILED DESCRIPTION

[0028] After long-term research, the inventors found that the process of copper electroplating hole filling in circuit boards generally includes: pretreatment (degreasing, water washing, micro-etching, water washing) → acid immersion → electroplating → water washing → drying; among them, sometimes an "additive pre-adsorption" step is added before acid immersion.

[0029] On the other hand, since copper electroplating in circuit boards may require multiple electroplating processes, the electroplating process may evolve into: pretreatment 1 (degreasing, water washing, micro-etching, water washing) → acid immersion → electroplating 1 → water washing → drying (optional) → pretreatment 2 (optional) → acid immersion → electroplating 2 → water washing → drying; wherein, steps from electroplating 1 to electroplating 2 can be repeated multiple times.

[0030] It is understandable that in both cases, direct current is used in the electroplating process. However, there is another case where pulse current is used for electroplating; and the waveform of this pulse current has the following characteristics: (1) The forward current density is close to the current density during direct current plating; (2) The reverse current density is greater than the forward current density; (3) The reverse current duration is less than the forward current duration, and the ratio of the reverse current to the forward current duration is between 1:5 and 1:100, with 1:20 being the most common. (4) The forward and reverse pulse durations are very short, generally the reverse pulse duration is less than 20μs, with 1-5μs being the most common.

[0031] In terms of technical principles, DC electroplating blind hole filling utilizes the specific adsorption of additives on the surface of the plated workpiece, thereby redistributing the current on the surface of the plated workpiece to achieve a larger current in the hole; the forward part of pulse electroplating hole filling is the same as the principle of DC plating, and the reverse part can enhance the specific adsorption of additives on the surface of the plated workpiece, thereby making the current in the blind hole larger during current redistribution; the current density in the blind hole is greater than that on the board surface, which is the basic principle of electroplated copper hole filling.

[0032] The "additive pre-adsorption" step specifically involves the specific adsorption of the corresponding additives before electroplating to enhance the specific adsorption effect of the additives during electroplating, thereby increasing the current density in the blind hole, shortening the electroplating time, and reducing electroplating defects. This "additive pre-adsorption" can be achieved through "immersion" or "electroplating"; however, "immersion" or "electroplating" alone is not enough; to achieve the best results, an "acceleration" process is often required.

[0033] However, all the electroplating methods mentioned above have one thing in common: that is, electroplating is completed in one go for a certain purpose. For example, the first process mentioned is the most common. When it is necessary to fill the blind hole, it is necessary to change the current density, electroplating time, optimize the electroplating solution, etc. to ensure that the blind hole can be completely filled in one electroplating. The second process that evolved from it includes multiple electroplating; it is divided into three categories: one is that the purpose of multiple electroplating is different, for example, the first electroplating is flash plating to thicken the seed layer; the second electroplating is to fill the hole. There are significant differences in the plating solution and parameters of these two electroplatings. The plating tanks for this type of multiple electroplating must be different. The second type is that the plating solution is the same for multiple times, but the subsequent electroplating is to make up for the defects of the previous electroplating. Generally, a pause is required between each electroplating for quality inspection; the plating tanks for the first two types are discontinuous. The third type is that the plating solution is the same for multiple times, but pulse and DC are used to fill the through holes respectively; the purposes of the pulse section and DC section are different, the pulse section is to seal the middle of the through hole to obtain two blind holes, and the DC section is to fill the remaining two blind holes.

[0034] At present, in the actual production process, the thickness-to-diameter ratio (hole depth: hole diameter) of blind holes in circuit boards is generally controlled at a specification of <0.8:1, and the depth of blind holes that require filling rarely exceeds 120μm; among them, in blind hole filling with hole diameter controlled within 120μm and hole depths of 140μm, 180μm, and 220μm, the "local pre-adsorption of additives" solution can speed up the filling speed and reduce filling defects, but there will still be problems such as long filling time and incomplete filling.

[0035] In order to effectively improve the efficiency of electroplating hole filling, shorten the hole filling time, and effectively fill the blind holes of the circuit board, the present application provides a circuit board electroplating method and a circuit board. The present application is further described in detail below in conjunction with the accompanying drawings and examples. It is particularly pointed out that the following examples are only used to illustrate the present application and do not limit the scope of the present application. Similarly, the following examples are only some embodiments of the present application and not all embodiments. All other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0036] References to "embodiments" in this application mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0037] See also Figure 1a-Figure 1f ,in, Figure 1aThis is a flow chart of the first embodiment of the method for manufacturing a circuit board of the present application. Figure 1b-1f yes Figure 1a The structural diagram of an embodiment corresponding to S11-S14 in FIG. This embodiment includes the following steps:

[0038] S11: performing preliminary processing on the circuit board to be electroplated to form a blind hole on one side of the circuit board.

[0039] Specifically, if Figure 1b As shown, before the circuit board 102 to be electroplated is electroplated, it is usually inevitable to perform preliminary processing on it. For example, the circuit board 102 to be electroplated is first cut, inner layer patterning is made, browning, pressing, drilling, copper plating and other reasonable process flows are carried out to form a blind hole 1021 on one side surface of the circuit board 102 arranged on the carrier 101, which will not be elaborated one by one here.

[0040] S12: electroplating the preliminarily treated circuit board using an electroplating solution and additives.

[0041] Furthermore, if Figure 1c As shown, after a blind hole 1021 is formed on one side of the preliminarily processed circuit board 102, the circuit board 102 is electroplated. For example, the preliminarily processed circuit board 102 is immersed in a plating tank containing a plating solution (not shown) and an additive 104, and powered by a DC power supply, so as to form a plating layer 103 on one side of the circuit board 102 and the bottom and side wall of the blind hole 1021.

[0042] The additive 104 specifically includes an accelerator 1041, and as Figure 1d As shown, by electroplating the preliminarily treated circuit board 102, the accelerator 1041 is adsorbed onto the electroplated layer 103 formed on one side of the circuit board 102 and the bottom and sidewalls of the blind hole 1021. In other embodiments, the additive 104 may further include an inhibitor 1042 and / or a leveler 1043, which is not limited in this application.

[0043] It should be noted that the electroplating solution specifically refers to a solution that can provide metal ions, such as a copper sulfate solution, so that a plating layer 103 can be formed on one side of the circuit board 102 and the bottom and sidewall of the blind hole 1021 through electroplating.

[0044] The accelerator 1041 is specifically composed of a small molecule compound containing a thiol group and a sulfonate group or a benzene ring. It can be adsorbed on the surface of the copper coating and continuously transferred to the outermost surface of the coating during the electroplating process, and has the effect of reducing the electrochemical polarization of the electroplated copper.

[0045] S13: electrolyzing the circuit board after the first electroplating to remove the accelerator adsorbed on one side of the circuit board after the first electroplating, and retaining the accelerator adsorbed on the bottom and part of the side wall of the blind hole.

[0046] Furthermore, if Figure 1e As shown, the circuit board 102 after one electroplating is subjected to one electrolysis, for example, the circuit board 102 is immersed in an electrolytic tank containing an electrolyte and subjected to electrolysis to dissolve a portion of the electroplating layer 103 on one side of the circuit board 102, thereby removing the accelerator 1041 adsorbed on one side of the circuit board 102 after the one electroplating, and only retaining the accelerator 1041 adsorbed near the bottom of the blind hole 1021, thereby forming a specific adsorption effect of the accelerator 1041.

[0047] It should be noted that the specific adsorption of the additive 104 means that during the electroplating process, different components of the additive 104 have different adsorption concentrations at different locations on the surface of the plated workpiece.

[0048] S14: performing secondary electroplating on the circuit board after the primary electrolytic treatment.

[0049] Furthermore, if Figure 1f As shown, the circuit board 102 after the primary electrolysis treatment is subjected to secondary electroplating to further form an electroplating filling layer 105 on the electroplating layer 103 to gradually fill the entire blind hole 1021 .

[0050] It is understandable that the electroplating filling layer 105 is the same as the electroplating layer 103 , but is distinguished here for the convenience of description.

[0051] In one embodiment, the additive 104 used in the secondary electroplating may further include an inhibitor 1042 and a leveler 1043 , which will not be described in detail here.

[0052] It should be noted that the inhibitor 1042 (also known as a wetting agent or carrier) is a substance used to retard or slow down chemical reactions, having the opposite effect to the accelerator 1041. It does not stop the electrochemical reaction; instead, it increases its polarization, thereby inhibiting the copper electroplating rate. The leveler 1043, on the other hand, is added to the electroplating solution to improve the flatness of the coating and enhance the differential adsorption of the additives 104, especially the accelerator 1041, resulting in a coating smoother than the substrate surface.

[0053] It is understandable that the above scheme adsorbs the additive 104 through "one-time electroplating", and then uses a short period of "one-time electrolysis" to achieve the specific adsorption of the accelerator 1041, thereby enhancing the specific adsorption effect of the additive 104 during "secondary electroplating" to quickly achieve electroplating hole filling, thereby effectively improving the efficiency of electroplating hole filling and shortening the hole filling time.

[0054] In one embodiment, the "primary electroplating" is specifically used for flash plating or via filling, while simultaneously adsorbing the accelerator 1041, while the "secondary electroplating" is used for via filling. Therefore, the "primary electroplating" and "secondary electroplating" use different electroplating solutions, for example, different concentrations of the copper sulfate solution included, to distinguish and correspond to different electroplating scenarios.

[0055] Furthermore, in one embodiment, after the above S13 and before S14, it further specifically includes: repeatedly executing the above S12 and S13 in sequence at least once.

[0056] It is understandable that in order to ensure that the blind holes 1021 formed on the circuit board 102 are filled more quickly, especially to ensure that the blind holes 1021 in the circuit board 102 with a high aspect ratio can be effectively filled, after the above-mentioned S13 and before S14, the circuit board 102 can be alternately electroplated and electrolyzed at least once, and it is ensured that between each two adjacent electroplating treatments, the electroplated circuit board 102 is subjected to an electrolysis treatment to gradually form a plating filling layer 105 on the electroplating layer 103, until the secondary electroplating is used to make the plating filling layer 105 fill the entire blind hole 1021.

[0057] It can be seen from this that compared with the existing electroplating method: the present application continuously uses "one-time electroplating" to adsorb the additive 104, and then uses a short time of "one-time electrolysis" to achieve "local pre-adsorption of the additive"; then "one-time electroplating" is performed to quickly fill the hole and adsorb the additive 104, and then a short time of "one-time electrolysis" is used to achieve "local pre-adsorption of the additive", and they are performed alternately in sequence, that is, by repeating the above steps according to the hole depth of the blind hole 1021, the rapid growth of the electroplated filling layer 105 in the hole of the "local pre-adsorption of the additive" method can be maintained for a long time, while avoiding the problem of too long filling time and inability to fill the blind hole 1021 in the one-time "local pre-adsorption of the additive" technology.

[0058] It should be noted that the “additive pre-soaking” or “additive local pre-adsorption” refers to the adsorption of the additive 104 on the surface of the plated workpiece before electroplating.

[0059] Furthermore, in one embodiment, the above S12 further specifically includes: electroplating the preliminarily treated circuit board 102 once using the electroplating solution in forced convection.

[0060] It is understandable that in order to ensure that the bottom of the blind hole 1021 of the circuit board 102 is electroplated more quickly and effectively, it is also necessary to ensure that the circuit board 102 after preliminary treatment by immersing in the electroplating solution is in strong convection. For example, by circulating and stirring the electroplating solution, the circuit board 102 is always in strong convection to perform an electroplating treatment on it.

[0061] Furthermore, in one embodiment, the above S12 further specifically includes: performing an electroplating treatment on the preliminarily treated circuit board 102 using an electroplating solution for a duration of 5-60 minutes.

[0062] Furthermore, in one embodiment, the above S13 further specifically includes: performing an electrolysis treatment for a duration of 5-120 seconds on the circuit board 102 after the first electroplating.

[0063] It can be seen from this that compared with existing electroplating methods: this application introduces a short-term (5-120s) "electrolysis" process between multiple electroplating processes to achieve the "accelerator pre-adsorption" method. On the one hand, "electrolysis" replaces the role of "micro-etching and other oxidants". On the other hand, multiple "electrolysis" is used to achieve the effect of multiple "accelerator pre-adsorption" in one electroplating process, thereby strengthening the use effect of the "accelerator local pre-adsorption" principle. In addition, this application is significantly different from pulse electroplating. That is, because this method uses a DC power supply, the duration of the forward current (electroplating output current) and the reverse current (electrolysis output current) are orders of magnitude different from those of pulse electroplating.

[0064] Furthermore, in one embodiment, the above S13 further specifically includes: performing an electrolytic treatment on the plated circuit board 102 using an electrolytic solution.

[0065] It is understandable that the electrolytic treatment performed on the plated circuit board 102 is specifically to immerse it in an electrolytic tank containing an electrolytic solution to electrolyze it.

[0066] Optionally, the electrolytic solution is different from the electroplating solution. In other embodiments, the electrolytic solution may also be the same as the electroplating solution, which is not limited in this application.

[0067] Optionally, the electrolytic solution includes acid ions, such as sulfate ions, chlorate ions, and any other reasonable acid ions, or further includes other reasonable solutions, which is not limited in this application.

[0068] Optionally, when the circuit board 102 needs to be subjected to multiple electroplating and electrolysis treatments, the electroplating solutions used in each of the two electroplating treatments are different, for example, the concentrations of the corresponding copper sulfate solutions are different, or the concentrations of other main components are different, so that the blind hole 1021 can be matched with the current electroplating scene to achieve better electroplating effect and electroplating efficiency; and the electrolytic solutions used in each of the two electrolysis treatments can also be different, so that the blind hole 1021 can be matched with the current electrolysis scene to achieve better electrolysis effect and electrolysis efficiency. In other embodiments, the electroplating solution can also remain consistent, and the electrolytic solution can also remain consistent, which is not limited in this application.

[0069] In one embodiment, if Figure 1g and Figure 1h As shown, Figure 1g This is a side view of the electroplating tank and electrolytic tank used in a specific application scenario of the circuit board electroplating method of this application. Figure 1h yes Figure 1g A top view of a plating tank and an electrolytic tank in a specific embodiment. The circuit board electroplating method in this embodiment specifically utilizes multiple plating tanks and electrolytic tanks connected end to end, such as plating tank 1, plating tank 2, ..., plating tank N+1 (N is a positive integer greater than 1), and electrolytic tank 1, electrolytic tank 2, ..., electrolytic tank N, so as to alternately perform multiple electroplating and electrolysis treatments on the circuit board 102. Specifically, the process is performed using a VCP (Vertical Conveyor Plating) line, a gantry line, or a horizontal line.

[0070] It should be noted that a VCP line generally refers to a production line used for electroplating acid- and alkali-resistant materials used in various chemical tanks. This VCP line, used for copper plating on PCBs, utilizes a jet copper plating process and a vertical continuous conveyor system for full-plate (one-pass) copper plating. The advantages of vertical continuous plating include: stable plating performance: all workpieces are continuously moved from one side of the plating tank to the other, with each workpiece moving at the same speed.

[0071] A gantry line is an automatic production line, available in single or double gantry configurations. Once the PCBs are mounted, they automatically run. This is a gantry-style production line, typically referring to an electroplating line. Simply put, it's a vertical line with an overhead crane spanning two guide rails that moves racks from fixed slots at fixed times according to a program to complete production.

[0072] Horizontal and vertical electroplating methods and principles are identical, both requiring a positive and negative electrode. However, the significant difference is that in vertical electroplating, the parts are positioned vertically and secured by a fixture, while in horizontal electroplating, the parts move horizontally on rollers. Horizontal electroplating offers better enclosure and a smaller footprint.

[0073] It is understandable that multiple plating tanks contain the same or different plating solutions, and multiple electrolytic tanks contain the same or different electrolytic solutions, and the electrolytic solutions and the electroplating solutions can be the same or different; the circuit board 102 is specifically immersed in and passes through the plating tank 1, electrolytic tank 1, electroplating tank 2, electrolytic tank 2,..., electrolytic tank N, and electroplating tank N+1 from one side of the electroplating tank 1, so as to alternately perform electroplating and electrolysis treatment on the circuit board 102.

[0074] Among them, such as Figure 1hAs shown, multiple electroplating tanks and multiple electrolytic tanks are connected to each other, and the corresponding electroplating solutions and electrolytic solutions contained therein are the same, and the corresponding sub-tanks are also connected to each other for circulation and alternation of the tank solutions.

[0075] In other embodiments, Figure 1i As shown, Figure 1i yes Figure 1g A top view of another specific embodiment of the electroplating tank and the electrolytic tank, with Figure 1h The difference is that the sub-tanks of multiple electroplating tanks are connected to each other, while the sub-tanks of multiple electrolytic tanks are connected to each other but not to the electroplating tank, so that the electroplating solution and the electrolytic solution can be circulated alternately, and the solid waste that may exist in the waste solution after electrolysis can be specially treated in a targeted manner.

[0076] And as Figure 1i As shown, Figure 1j yes Figure 1g A top view of another embodiment of the electroplating tank and the electrolytic tank, Figure 1h The difference is that multiple electroplating tanks and multiple electrolytic tanks can also use independent sub-tanks, which is not limited in this application.

[0077] In another embodiment, if Figure 1k and Figure 1h As shown, Figure 1k This is a side view of an electroplating tank and an electrolytic tank used in another specific application scenario of the circuit board electroplating method of the present application. Figure 11 yes Figure 1k A top view of a specific embodiment of the electroplating tank and electrolytic tank in FIG. The electroplating method for the circuit board in this embodiment specifically uses electroplating tank 11, electroplating tank 12, ..., electroplating tank 1(N+1) (N is a positive integer greater than 1), and electrolytic tank 11, electrolytic tank 12, ..., electrolytic tank 1N, with each adjacent solution tank being spaced apart from each other and not connected, so as to alternately perform multiple electroplating and electrolysis treatments on the circuit board 102, and specifically uses a VCP line or a gantry line for the process.

[0078] Among them, such as Figure 11 As shown, when multiple electroplating solutions are the same as each other but different from multiple electrolytic solutions, the sub-tanks of multiple electroplating tanks are connected to each other, and the sub-tanks of multiple electrolytic tanks are connected to each other but not to the electroplating tanks, so that the electroplating solutions and the electrolytic solutions can be circulated alternately, and solid waste that may exist in the waste solution after electrolysis can be specially treated in a targeted manner.

[0079] In other embodiments, Figure 1m As shown, Figure 1m yes Figure 1kIn the top view of another specific embodiment of the electroplating tank and the electrolytic tank, when the multiple electroplating solutions and the multiple electrolytic solutions are different, the multiple electroplating tanks and the multiple electrolytic tanks can also use independent sub-tanks from each other, and this application does not limit this.

[0080] Furthermore, in one embodiment, after the above S11 and before S12 , the following further specifically includes: performing acid immersion treatment on the circuit board 102 after the preliminary treatment.

[0081] It should be noted that acid leaching refers to a mineral leaching process that uses an aqueous solution of an inorganic acid as a leaching agent to facilitate the subsequent electroplating process.

[0082] Furthermore, in one embodiment, after the above S14, the following further specifically includes: washing and drying the circuit board 102 after the secondary electroplating in sequence.

[0083] It is understandable that after completing the water washing and drying treatment of the circuit board 102 after the secondary electroplating, the electroplated circuit board 102 product can be obtained.

[0084] In the above scheme, the electroplating method of the circuit board 102 forms a blind hole 1021 on one side surface of the circuit board 102, and after electroplating the circuit board 102 after the preliminary treatment with the electroplating solution and the additive 104, the accelerator 1041 adsorbed on the one side surface of the circuit board 102 after the electroplating can be removed by electrolyzing the circuit board 102 after the single electroplating, while retaining the accelerator 1041 adsorbed on the bottom and side wall of the blind hole 1021, thereby enhancing the specific adsorption effect of the additive 104, ensuring that the secondary electroplating of the circuit board 102 after the single electrolysis treatment can quickly fill the blind hole 1021 of the circuit board 102, thereby effectively improving the efficiency of the electroplating hole filling and shortening the hole filling time.

[0085] See also Figure 2 , Figure 2 This is a flow chart of the second embodiment of the electroplating method for a circuit board of the present application. The electroplating method for a circuit board of this embodiment is Figure 1a A schematic flow chart of a detailed embodiment of a method for electroplating a circuit board in FIG. 1 , wherein the embodiment includes the following steps:

[0086] S21: performing preliminary processing on the circuit board to be electroplated to form a blind hole on one side of the circuit board.

[0087] Among them, S21 and Figure 1a For details, please refer to S11 and its related text descriptions, which will not be repeated here.

[0088] S22: Electroplating the preliminarily treated circuit board once using a first DC power supply and an electroplating solution and an additive.

[0089] Specifically, a first DC power supply is used to power a plating tank containing a plating solution and an additive, so as to perform a DC electroplating on the circuit board after preliminary treatment, thereby forming a plating layer on one side of the circuit board and the bottom and side walls of the blind hole, and allowing the accelerator to be adsorbed on the corresponding plating layer formed on one side of the circuit board and the bottom and side walls of the blind hole.

[0090] Optionally, the duration of one electroplating treatment is 5-60 minutes.

[0091] S23: electrolyzing the circuit board after the first electroplating using a second DC power supply to remove the accelerator adsorbed on one side of the circuit board after the first electroplating, and retaining the accelerator adsorbed on the bottom and part of the side wall of the blind hole.

[0092] Furthermore, a second DC power supply is used to power an electrolytic tank containing an electrolyte to perform a first electrolysis on the circuit board after the first electroplating to dissolve a portion of the electroplated layer on one side of the circuit board, thereby removing the accelerator adsorbed on the one side of the circuit board after the first electroplating, and retaining only the accelerator adsorbed on the bottom and part of the side wall of the blind hole. Specifically, the closer to the side of the circuit board, the less accelerator is retained, and the closer to the bottom of the blind hole, the more complete the accelerator is retained, thereby forming a specific adsorption effect of the additive.

[0093] The current density outputted by the first DC power supply to the circuit board is greater than the current density outputted by the second DC power supply to the circuit board.

[0094] Optionally, the duration of one electrolysis treatment is 5-120 seconds.

[0095] S24: performing secondary electroplating on the circuit board after the primary electrolytic treatment.

[0096] Among them, S24 and Figure 1a For details, please refer to S14 and its related text descriptions, which will not be repeated here.

[0097] It can be understood that compared with the existing electroplating method: this embodiment adopts continuous multiple electroplating, and there is electrolysis between electroplating; it is also significantly different from pulse electroplating. The "forward current duration" (electroplating time) and "reverse current duration" (electrolysis time) of this application are longer, and there is no need to use a pulse power supply, only multiple DC power supplies need to be combined.

[0098] The beneficial effect of the present application is that, unlike the prior art, the circuit board electroplating method of the present application forms a blind hole on one side of the circuit board, and after electroplating the circuit board after the preliminary treatment with an electroplating solution and an additive, the accelerator adsorbed on one side of the circuit board after electroplating can be removed by electrolyzing the circuit board after the first electroplating, and the accelerator adsorbed on the bottom and part of the side wall of the blind hole can be retained, thereby enhancing the effect of the specific adsorption of the additive, ensuring that the secondary electroplating of the circuit board after the first electrolysis treatment can quickly fill the blind hole of the circuit board, thereby effectively improving the efficiency of electroplating hole filling and shortening the hole filling time.

[0099] The above is only an implementation method of the present application and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the description and drawings of this application, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A method for electroplating a circuit board, characterized in that: The electroplating method of the circuit board comprises: Performing preliminary processing on a circuit board to be electroplated to form a blind hole on one side of the circuit board; Electroplating the preliminarily treated circuit board once using an electroplating solution and an additive; wherein the additive includes an accelerator; performing electrolysis on the circuit board after the first electroplating to remove the accelerator adsorbed on one side of the circuit board after the first electroplating, and retaining the accelerator adsorbed on the bottom and part of the side wall of the blind hole; Repeating the steps of electroplating the preliminarily treated circuit board with the electroplating solution and the additive and electrolyzing the electroplated circuit board at least once to remove the accelerator adsorbed on one side of the circuit board after the electroplating and retaining the accelerator adsorbed on the bottom and part of the sidewall of the blind hole; The circuit board after the primary electrolytic treatment is subjected to secondary electroplating.

2. The electroplating method of a circuit board according to claim 1, wherein: The step of electroplating the preliminarily treated circuit board using an electroplating solution and an additive comprises: The circuit board after the preliminary treatment is electroplated once using the electroplating solution in forced convection.

3. The electroplating method of a circuit board according to claim 1, wherein: The step of electroplating the preliminarily treated circuit board using an electroplating solution and an additive comprises: The circuit board after the preliminary treatment is subjected to an electroplating treatment lasting 5-60 minutes using the electroplating solution.

4. The electroplating method for a circuit board according to claim 1 or 3, characterized in that: The step of performing a primary electrolysis on the circuit board after the primary electroplating comprises: The circuit board after the first electroplating is subjected to a first electrolysis treatment lasting 5-120 seconds.

5. The electroplating method for a circuit board according to claim 1, wherein: The step of electroplating the preliminarily treated circuit board using an electroplating solution and an additive comprises: Using a first DC power supply and the electroplating solution and the additive to electroplate the preliminarily treated circuit board once; The step of performing a primary electrolysis on the circuit board after the primary electroplating comprises: Using a second DC power supply to perform electrolysis on the circuit board after the first electroplating; The current density outputted from the first DC power supply to the circuit board is greater than the current density outputted from the second DC power supply to the circuit board.

6. The electroplating method for a circuit board according to claim 1, wherein: The step of performing a primary electrolysis on the circuit board after the primary electroplating comprises: The electroplated circuit board is subjected to an electrolytic treatment using an electrolytic solution; wherein the electrolytic solution is different from the electroplating solution.

7. The electroplating method for a circuit board according to claim 6, wherein: The electrolytic solution includes acid ions.

8. The electroplating method for a circuit board according to claim 1, wherein: The electroplating solutions used in two electroplating operations are different.

9. A circuit board, characterized in that: The circuit board is obtained by the electroplating method for a circuit board according to any one of claims 1 to 8.

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