An electroplating copper plating solution and an electroplating method applicable to through-hole copper filling of a printed circuit board

Abstract

An electroplated copper plating solution and electroplating method suitable for through-hole copper filling of printed circuit boards, which belong to the field of electroplating technology. An electroplated copper plating solution suitable for through-hole copper filling of printed circuit boards is prepared from copper sulfate pentahydrate, sulfuric acid, halogen ions, and a combined additive; in the present invention, the synergistic effect of basic blue 1 and disodium 5'-adenylate in the composite leveling agent can achieve the through-hole copper plating filling ability, effectively improve the uniformity of the copper interconnect coating, and enhance the quality of the interconnect structure. In the present invention, first, a printed circuit board with through-holes is pretreated, and the pretreated printed circuit board with through-holes is immersed in an electroplated copper plating solution suitable for through-hole copper filling of printed circuit boards, and a unidirectional pulse electroplating process is used to electroplate the through-holes of the printed circuit board with through-holes for a period of time to obtain an electroplated printed circuit board; in the present invention, the composite leveling agent combined with the pulse process results in better coating uniformity, low surface copper thickness in the through-holes, and a significant increase in the TP value.

Description

Technical Field

[0001] The present invention belongs to the technical field of electroplating, and particularly relates to an electroplating copper plating solution and an electroplating method suitable for through-hole copper filling of printed circuit boards. Background Art

[0002] In the technological wave of the 21st century, more stringent requirements for miniaturization, functionality, and high integration of electronic products have been put forward in multiple fields such as aerospace, communication, industrial manufacturing, and energy. As the heart of electronic products, a printed circuit board (PCB) bears the interconnection layout of electronic components. In the manufacturing process of PCB, current electroplating technology is the most mature and reliable micro-nano scale electronic component interconnection and forming process, and an acidic copper sulfate aqueous solution is widely used as a commercial electroplating solution system due to its maturity. However, during the PCB electroplating process, the scale effect caused by the complex hole structure poses kinetic limitations on the diffusion mass transfer of local copper ions under the action of an electric field. With the extension of the electroplating time, the intensification of the concentration polarization effect leads to a lower copper deposition rate inside the hole than outside the hole. At the same time, the tip effect of the hole edge structure will induce a change in electrochemical polarization, and both will directly affect the density and uniformity of the coating. These problems have a serious negative impact on the quality of PCB copper interconnection. Therefore, regulating the growth process of electroplated copper and optimizing the coating quality have become the key to ensuring the practical performance of PCB. And upgrading electroplating processes, such as adding functional plating solution additives, switching electroplating modes, and adjusting electroplating physical conditions, are all feasible technical approaches.

[0003] In the existing PCB copper electroplating process, various organic compounds are usually selected as accelerators, inhibitors, and leveling agents respectively, and the compounding method of the three is used to trigger the synergistic and antagonistic effects to ensure the plating rate difference at the hole positions with different geometric structures, and finally achieve the copper deposition goal from the inside out or from the bottom up. The brightener, also known as the accelerator, usually refers to organic molecules containing sulfonate groups and mercapto groups. These molecules are small in size and their function is to accelerate the formation of the copper layer. On the other hand, high-molecular oxygen-containing compounds such as polyethylene glycol and polypropylene glycol, as grain refiners, play a role in slowing down the copper crystallization rate during electroplating. In addition, the leveling agent, also known as the throwing power agent or the second type of inhibitor, is mainly composed of nitrogen-containing organic compounds with a large molecular weight. Due to their positive charge characteristics during electroplating, these substances tend to preferentially adsorb at the protruding parts of the cathode and the current-dense areas, thereby inhibiting the deposition of copper at the hole opening to achieve the purpose of leveling. Based on the functional effects generated by the compounding of the three additives, the plating rate can be precisely controlled to enable the inside-out growth of copper in the micro-holes, ultimately meeting the practical requirements of copper interconnections. The leveling agents used in the current mature production processes are generally single components. Due to the substitution adsorption mechanism behavior that often exists among inhibitors, accelerators, and leveling agents, the function of a single leveling agent cannot be maximized, so the ability to regulate the growth behavior of the through-hole copper plating layer with a high aspect ratio is very limited. At the same time, the cathode polarization caused by the direct current electroplating mode in the traditional manufacturing process results in an excessive copper ion mass transfer rate difference at different positions of the hole, which also has a negative impact on the function of the additives, so the coating quality obtained under high-current conditions cannot meet the practical requirements. To sum up, developing a compound component of the electroplating leveling agent that can achieve high-quality copper interconnection and reasonably optimizing the electroplating process conditions not only has important significance for the development of semiconductor manufacturing technology, but also shows great application potential and market prospects in the future electronic manufacturing industry. Summary of the Invention

[0004] To solve the above existing problems, the present invention provides an electroplating copper plating solution and an electroplating method suitable for through-hole copper filling of printed circuit boards.

[0005] An electroplating copper plating solution suitable for through-hole copper filling of printed circuit boards is prepared from copper sulfate pentahydrate, sulfuric acid, halogen ions, and a combined additive;

[0006] The combined additive includes a composite leveling agent, an accelerator, and an inhibitor;

[0007] In the copper electroplating solution suitable for through-hole copper filling of printed circuit boards, the concentration of copper sulfate pentahydrate is 75 g / L, the concentration of sulfuric acid is 240 g / L, the concentration of halogen ions is 60 mg / L, the concentration of the composite leveling agent is 30 mg / L to 300 mg / L, the concentration of the accelerator is 2 mg / L to 3 mg / L, and the concentration of the inhibitor is 100 mg / L to 750 mg / L.

[0008] The method of electroplating using a copper electroplating solution suitable for through-hole copper filling of printed circuit boards is specifically completed according to the following steps:

[0009] I. Pretreat the printed circuit board with through-holes:

[0010] First, immerse the printed circuit board with through-holes in a degreasing solution at a temperature of 70 °C to 90 °C for 5 min to 10 min. After taking it out, wash it with room temperature water for 1 min to 3 min, then immerse it in acetone for 3 min to 8 min. After taking it out, wash it with room temperature water for 1 min to 3 min, then immerse it in sulfuric acid with a mass fraction of 10% for 5 min to 8 min. After taking it out, wash it with room temperature water for 1 min to 3 min, immerse it in water for 1 min to 3 min, and then take it out and wash it with room temperature water for 1 min to 3 min to obtain a pretreated printed circuit board with through-holes;

[0011] II. Immerse the pretreated printed circuit board with through-holes in the copper electroplating solution suitable for through-hole copper filling of printed circuit boards, and use a unidirectional pulse electroplating process to electroplate the through-holes of the printed circuit board with through-holes for a period of time to obtain an electroplated printed circuit board;

[0012] In step II, the cathode current of the unidirectional pulse electroplating process is set at 1.5 ADS to 4.5 ADS, the pulse peak current density is 2.5 A / dm 2 ~4.5 A / dm 2 , the pulse time is 15 ms to 30 ms, the duty cycle is 40% to 60%, and the electroplating duration is 45 min to 80 min.

[0013] The principle of the present invention:

[0014] The present invention utilizes the synergistic effect of basic blue 1 and disodium 5'-adenylic acid in the composite leveling agent to achieve the through-hole copper plating filling ability, effectively improve the uniformity of the copper interconnect coating, and enhance the quality of the interconnect structure.

[0015] Compared with the prior art, the present invention has the following advantages:

[0016] I. The present invention is applicable to high-current working conditions, effectively shortens the actual production time of PCB metal interconnections, and reduces the manufacturing cost;

[0017] II. The present invention is applicable to the electroplating of vias in printed circuit boards;

[0018] III. In the present invention, the composite leveling agent combined with the pulse process results in better coating uniformity, lower surface copper thickness in vias, and a significantly increased TP value. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 are the molecular structures of basic blue 1 and disodium 5'-adenylic acid used in the present invention;

[0020] Figure 2 is a three-dimensional microscopic image of the copper coating on the via of a printed circuit board after electroplating. In the figure, a is Comparative Example 1, b is Comparative Example 2, and c is Example 1;

[0021] Figure 3 is a metallographic section diagram of the cross-section of the copper coating on the via of a printed circuit board after electroplating. In the figure, (a) is Comparative Example 3, (b) is Example 1, and b is Comparative Example 2;

[0022] Figure 4 is a metallographic section diagram of the cross-section of the copper coating on the via of a printed circuit board after electroplating. In the figure, (a) is Example 2 and (b) is Example 3. DETAILED DESCRIPTION OF THE INVENTION

[0023] DETAILED DESCRIPTION OF THE INVENTION I: A copper electroplating solution applicable to filling copper in vias of printed circuit boards according to this embodiment is prepared from cupric sulfate pentahydrate, sulfuric acid, halogen ions, and a combined additive;

[0024] The combined additive includes a composite leveling agent, an accelerator, and an inhibitor;

[0025] In the copper electroplating solution applicable to filling copper in vias of printed circuit boards, the concentration of cupric sulfate pentahydrate is 75 g / L, the concentration of sulfuric acid is 240 g / L, the concentration of halogen ions is 60 mg / L, the concentration of the composite leveling agent is 30 mg / L - 300 mg / L, the concentration of the accelerator is 2 mg / L - 3 mg / L, and the concentration of the inhibitor is 100 mg / L - 750 mg / L.

[0026] DETAILED DESCRIPTION OF THE INVENTION II: The difference between this embodiment and DETAILED DESCRIPTION OF THE INVENTION I is that the accelerator is sodium dodecyl sulfate, sodium 3-mercapto-1-propanesulfonate, sodium 2,3-dimercaptopropanesulfonate, 1,3-propanedithiol, sodium thiazolinyl dithiopropanesulfonate, or sodium N,N-dimethyldithiocarbamoylpropane sulfonate. Other steps are the same as those in DETAILED DESCRIPTION OF THE INVENTION I.

[0027] DETAILED DESCRIPTION OF THE INVENTION III: The difference between this embodiment and either DETAILED DESCRIPTION OF THE INVENTION I or II is that the inhibitor is polyethylene glycol. Other steps are the same as those in DETAILED DESCRIPTION OF THE INVENTION I or II.

[0028] Embodiment 4: The difference between this embodiment and any one of Embodiments 1 to 3 is that the molecular weight of the polyethylene glycol is 8000 - 20000. Other steps are the same as those in Embodiments 1 to 3.

[0029] Embodiment 5: The difference between this embodiment and any one of Embodiments 1 to 4 is that the composite leveling agent is a mixture of basic blue 1 and disodium 5'-adenylic acid, and the mass ratio of basic blue 1 to disodium 5'-adenylic acid is 120:30. Other steps are the same as those in Embodiments 1 to 4.

[0030] Embodiment 6: The difference between this embodiment and any one of Embodiments 1 to 5 is that the mass fraction of the sulfuric acid is 98%; the halogen ion is a chloride ion. Other steps are the same as those in Embodiments 1 to 5.

[0031] Embodiment 7: The difference between this embodiment and any one of Embodiments 1 to 6 is that in the electroplating copper plating solution applicable to through-hole copper filling of printed circuit boards, the concentration of copper sulfate pentahydrate is 75 g / L, the concentration of sulfuric acid is 240 g / L, the concentration of halogen ions is 60 mg / L, the concentration of the composite leveling agent is 50 mg / L - 150 mg / L, the concentration of the accelerator is 2 mg / L - 3 mg / L, and the concentration of the inhibitor is 200 mg / L - 500 mg / L. Other steps are the same as those in Embodiments 1 to 6.

[0032] Embodiment 8: This embodiment is a method for electroplating using an electroplating copper plating solution applicable to through-hole copper filling of printed circuit boards, and it is specifically completed according to the following steps:

[0033] I. Pretreat the printed circuit board with through-holes:

[0034] First, immerse the printed circuit board with through-holes in a degreasing solution at a temperature of 70°C - 90°C for 5 min - 10 min, take it out and wash it with room temperature water for 1 min - 3 min, then immerse it in acetone for 3 min - 8 min, take it out and wash it with room temperature water for 1 min - 3 min, then immerse it in sulfuric acid with a mass fraction of 10% for 5 min - 8 min, take it out and wash it with room temperature water for 1 min - 3 min, immerse it in water for 1 min - 3 min, and then take it out and wash it with room temperature water for 1 min - 3 min to obtain a pretreated printed circuit board with through-holes;

[0035] II. Immerse the pretreated printed circuit board with through-holes in the electroplating copper plating solution applicable to through-hole copper filling of printed circuit boards, and use a unidirectional pulse electroplating process to electroplate the through-holes of the printed circuit board with through-holes for a period of time to obtain an electroplated printed circuit board;

[0036] In the unidirectional pulse electroplating process described in Step 2, the cathode current is set to 1.5 ADS to 4.5 ADS, the pulse peak current density is 2.5 A / dm 2 ~4.5 A / dm 2 , the pulse time is 15 ms to 30 ms, the duty cycle is 40% to 60%, and the electroplating duration is 45 min to 80 min.

[0037] Specific Embodiment Nine: The difference between this embodiment and any one of the first to eighth specific embodiments is that: the degreasing solution described in Step 1 is composed of NaOH, Na2SiO3·9H2O, Na3PO4·12H2O, Na2CO3 and water, and the concentration of NaOH is 0.2 mol·L -1 ~0.3 mol·L -1 , the concentration of Na2SiO3·9H2O is 0.03 mol·L -1 ~0.05 mol·L -1 , the concentration of Na3PO4·12H2O is 0.1 mol·L -1 ~0.2 mol·L -1 , the concentration of Na2CO3 is 0.40 mol·L -1 ~0.60 mol·L -1 . Other steps are the same as those in the first to eighth specific embodiments.

[0038] Specific Embodiment Ten: The difference between this embodiment and any one of the first to ninth specific embodiments is that: the size of the printed circuit board with through holes described in Step 1 is 10 cm × 5 cm, the diameter of the through hole is 300 μm, and the depth-to-diameter ratio is 10:1; the capacity of the Hull cell used for electroplating in Step 2 is 1.5 liters. Other steps are the same as those in the first to ninth specific embodiments.

[0039] The following examples are used to verify the beneficial effects of the present invention:

[0040] Example 1: An electroplating copper plating solution suitable for filling copper in through holes of printed circuit boards is prepared from copper sulfate pentahydrate, sulfuric acid, halogen ions and a combined additive;

[0041] The combined additive includes a composite leveling agent, an accelerator and an inhibitor;

[0042] The accelerator is sodium dodecyl sulfate;

[0043] The inhibitor is polyethylene glycol with a molecular weight of 10000;

[0044] The composite leveling agent is a mixture of basic blue 1 and 5'-adenosine monophosphate disodium salt, and the mass ratio of basic blue 1 to 5'-adenosine monophosphate disodium salt is 120:30;

[0045] The mass fraction of the sulfuric acid is 98%; the halogen ion is a chloride ion;

[0046] In the electroplating copper plating solution applicable to through-hole copper filling of printed circuit boards, the concentration of copper sulfate pentahydrate is 75 g / L, the concentration of sulfuric acid is 240 g / L, the concentration of halogen ions is 60 mg / L, the concentration of the composite leveling agent is 150 mg / L, the concentration of the accelerator is 2 mg / L, and the concentration of the inhibitor is 500 mg / L;

[0047] A method for electroplating using an electroplating copper plating solution applicable to through-hole copper filling of printed circuit boards is specifically completed according to the following steps:

[0048] I. Pretreat the printed circuit board with through-holes:

[0049] First, immerse the printed circuit board with through-holes in a degreasing solution at 80 °C for 5 min, take it out and wash it with room temperature water for 1 min, then immerse it in acetone for 5 min, take it out and wash it with room temperature water for 1 min, then immerse it in sulfuric acid with a mass fraction of 10% for 5 min, take it out and wash it with room temperature water for 1 min, immerse it in water for 1 min, and then take it out and wash it with room temperature water for 1 min to obtain a pretreated printed circuit board with through-holes;

[0050] In step I, the size of the printed circuit board with through-holes is 10 cm × 5 cm, the diameter of the through-hole is 300 μm, and the depth-to-diameter ratio is 10:1;

[0051] The degreasing solution described in step I is composed of NaOH, Na2SiO3·9H2O, Na3PO4·12H2O, Na2CO3 and water, where the concentration of NaOH is 0.25 mol·L -1 , the concentration of Na2SiO3·9H2O is 0.04 mol·L -1 , the concentration of Na3PO4·12H2O is 0.15 mol·L -1 , the concentration of Na2CO3 is 0.50 mol·L -1 ;

[0052] II. Immerse the pretreated printed circuit board with through-holes in the electroplating copper plating solution applicable to through-hole copper filling of printed circuit boards at 25 °C, and use a unidirectional pulse electroplating process to electroplate the through-holes of the printed circuit board with through-holes for a period of time to obtain an electroplated printed circuit board;

[0053] In step II, the cathode current of the unidirectional pulse electroplating process is set at 3 ADS, the pulse peak current density is 3 A / dm 2 , the pulse time is 30 ms, the duty cycle is 40%, and the electroplating duration is 80 min;

[0054] In Step 2, the Hull cell used for electroplating has a capacity of 1.5 liters.

[0055] Example 2: The difference between this example and Example 1 is that the composite leveling agent is a mixture of Basic Blue 1 and 5'-Adenylic acid disodium salt, and the mass ratio of Basic Blue 1 to 5'-Adenylic acid disodium salt is 100:50. Other steps and parameters are the same as those in Example 1.

[0056] Example 3: The difference between this example and Example 1 is that the composite leveling agent is a mixture of Basic Blue 1 and 5'-Adenylic acid disodium salt, and the mass ratio of Basic Blue 1 to 5'-Adenylic acid disodium salt is 140:10. Other steps and parameters are the same as those in Example 1.

[0057] Comparative Example 1: The difference between this example and Example 1 is that no leveling agent is used, that is, the combined additive includes an accelerator and an inhibitor. Other steps and parameters are the same as those in Example 1.

[0058] Comparative Example 2: The difference between this example and Example 1 is that the combined additive includes a leveling agent, an accelerator and an inhibitor; the leveling agent is Basic Blue 1, and the concentration of the leveling agent is 150 mg / L. Other steps and parameters are the same as those in Example 1.

[0059] Comparative Example 3: The difference between this example and Example 1 is that in Step 2, the printed circuit board with vias after pretreatment is immersed in an electroplating copper plating solution suitable for copper filling of vias in printed circuit boards, and the vias of the printed circuit board with vias are electroplated for a period of time using a direct current electroplating process to obtain an electroplated printed circuit board; the cathode current of the direct current electroplating process described in Step 2 is set at 3 ADS, and the electroplating duration is 80 min. Other steps and parameters are the same as those in Example 1.

[0060] Figure 2 It is a three-dimensional microscope image of the copper coating after electroplating the vias of the printed circuit board. In the figure, a is Comparative Example 1, b is Comparative Example 2, and c is Example 1;

[0061] From Figure 2 it can be seen that the roughness of a and b is higher than that of c; it shows that: compared with not using a leveling agent and using Basic Blue 1 alone as a leveling agent, the copper coating obtained by using the compound of Basic Blue 1 and 5'-Adenylic acid disodium salt as a leveling agent in Example 1 of the present invention has fine and smooth crystallization and excellent bright leveling ability.

[0062] Figure 3 It is a metallographic section diagram of the cross-section of the copper coating after electroplating the vias of the printed circuit board. In the figure, (a) is Comparative Example 3, (b) is Example 1, and b is Comparative Example 2;

[0063] From Figure 3 It can be seen that: within the 300-micron through-hole, Example 1 achieved high-quality interconnection of the compound leveling agent under pulsed current conditions, with a TP value reaching 95.8% and good coating uniformity. In contrast, for the sample with the compound leveling agent + DC electroplating mode (Control Example 3), the copper filling quality was poor, the average surface copper thickness was 22.63 microns, and the TP value was only 55.8%. The single leveling agent (Control Example 2) also showed poor effects under pulsed electroplating conditions, with an average surface copper thickness of 15.28 microns for the sample and a TP value of only 66.8%. This indicates that both the compound leveling agent and the pulsed electroplating mode are essential conditions for high-quality through-hole electroplating copper filling.

[0064] Figure 4 It is a metallographic section diagram of the copper coating cross-section after through-hole electroplating of the printed circuit board. In the figure, (a) is Example 2 and (b) is Example 3;

[0065] From Figure 4 It can be known that: after adjusting the concentration of the composite leveling agent, it can be seen that within the 300-micron through-hole, the copper filling quality of the sample in Example 2 was poor, the average surface copper thickness was 15.022 microns, and the TP value was only 57.7%; the copper filling quality of the sample in Example 3 was improved compared to Example 2, but the copper plating effect was still not good, with an average surface copper thickness of 15.204 microns and a TP value of 75.8%.

Claims

1. A method of electroplating using an electroplating copper plating solution suitable for through-hole copper filling of a printed circuit board, characterized in that The method is specifically completed according to the following steps: I. Pretreat the printed circuit board with vias: First, immerse the printed circuit board with vias in a degreasing solution at a temperature of 70°C to 90°C for 5 minutes to 10 minutes, take it out and wash it with room temperature water for 1 minute to 3 minutes, then immerse it in acetone for 3 minutes to 8 minutes, take it out and wash it with room temperature water for 1 minute to 3 minutes, then immerse it in sulfuric acid with a mass fraction of 10% for 5 minutes to 8 minutes, take it out and wash it with room temperature water for 1 minute to 3 minutes, immerse it in water for 1 minute to 3 minutes, and then take it out and wash it with room temperature water for 1 minute to 3 minutes to obtain the pretreated printed circuit board with vias; II. Immerse the pretreated printed circuit board with vias in an electroplating copper plating solution suitable for via filling of printed circuit boards, and use a unidirectional pulse electroplating process to electroplate the vias of the printed circuit board with vias for a period of time to obtain the electroplated printed circuit board; In step two, the cathode current of the unidirectional pulse electroplating process is set to 1.5 ADS to 4.5 ADS, and the pulse peak current density is 2.5 A / dm 2 to 4.5 A / dm 2 , the pulse time is 15 ms to 30 ms, the duty cycle is 40% to 60%, and the electroplating duration is 45 min to 80 min; The electroplating copper plating solution suitable for via filling of printed circuit boards is prepared from copper sulfate pentahydrate, sulfuric acid, halogen ions, and a combined additive; The combined additive includes a composite leveling agent, an accelerator, and an inhibitor; In the electroplating copper plating solution suitable for via filling of printed circuit boards, the concentration of copper sulfate pentahydrate is 75 g / L, the concentration of sulfuric acid is 240 g / L, the concentration of halogen ions is 60 mg / L, the concentration of the composite leveling agent is 30 mg / L to 300 mg / L, the concentration of the accelerator is 2 mg / L to 3 mg / L, and the concentration of the inhibitor is 100 mg / L to 750 mg / L; The composite leveling agent is a mixture of basic blue 1 and disodium 5'-adenylic acid, and the mass ratio of basic blue 1 to disodium 5'-adenylic acid is 120:

30.

2. The electroplating method using an electroplating copper plating solution suitable for through-hole copper filling of a printed circuit board according to claim 1, wherein The accelerator is sodium dodecyl sulfate, sodium 3-mercapto-1-propanesulfonate, sodium 2,3-dimercaptopropanesulfonate, 1,3-propanedithiol, sodium thiazolinyl dithiopropanesulfonate, or sodium N,N-dimethyldithiocarbamoylpropane sulfonate.

3. The electroplating method using an electroplating copper plating solution suitable for through-hole copper filling of a printed circuit board according to claim 1, characterized in that The inhibitor is polyethylene glycol.

4. The electroplating method using an electroplating copper plating solution suitable for through-hole copper filling of printed circuit boards according to claim 3, characterized in that The molecular weight of the polyethylene glycol is 8000 to 20000.

5. The electroplating method using an electroplating copper plating solution suitable for through-hole copper filling of a printed circuit board according to claim 1, characterized in that The mass fraction of the sulfuric acid is 98%; the halogen ion is chloride ion.

6. The electroplating method using an electroplating copper plating solution suitable for through-hole copper filling of a printed circuit board according to claim 1, characterized in that In the electroplating copper plating solution suitable for via filling of printed circuit boards, the concentration of copper sulfate pentahydrate is 75 g / L, the concentration of sulfuric acid is 240 g / L, the concentration of halogen ions is 60 mg / L, the concentration of the composite leveling agent is 50 mg / L to 150 mg / L, the concentration of the accelerator is 2 mg / L to 3 mg / L, and the concentration of the inhibitor is 200 mg / L to 500 mg / L.

7. The electroplating method using an electroplating copper plating solution suitable for through-hole copper filling of a printed circuit board according to claim 1, characterized in that The degreasing solution described in Step 1 is composed of NaOH, Na2SiO3·9H2O, Na3PO4·12H2O, Na2CO3 and water. The concentration of NaOH is 0.2mol·L -1 ~0.3mol·L -1 , the concentration of Na2SiO3·9H2O is 0.03mol·L -1 ~0.05mol·L -1 , the concentration of Na3PO4·12H2O is 0.1mol·L -1 ~0.2mol·L -1 , the concentration of Na2CO3 is 0.40mol·L -1 ~0.60mol·L -1 .

8. The electroplating method using an electroplating copper plating solution suitable for through-hole copper filling of a printed circuit board according to claim 1, characterized in that In step I, the size of the printed circuit board with vias is 10 cm × 5 cm, the via diameter is 300 μm, and the depth-to-diameter ratio is 10:1; in step II, the capacity of the Hull cell used for electroplating is 1.5 liters.

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