Acid copper plating solution for printed circuit board and application thereof

Abstract

The application discloses a kind of printed wiring board acidic copper plating bath and its application, belong to copper plating process technical field, including divalent copper ion, water-soluble chloride, sulfuric acid, divalent sulfide brightener, polyether compound, vinyl oxazole compound and distilled water, wherein divalent sulfide brightener, polyether compound and vinyl oxazole compound are used as the additive of acidic copper plating bath and can synergistic effect, improve the performance and characteristics of plating solution, improve the quality and excellent degree of copper plating layer, provide certain technical guarantee and advantage for the production and application of printed wiring board.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electroplating copper process, in particular to a kind of printed wiring board acidic copper plating solution and its application BACKGROUND

[0002] PCB is printed circuit board, which is an electronic platform made by providing conductive patterns for the connection of components on an insulating substrate using the method of photographic plating, and finally installing electronic components at the corresponding position. It can form electronic signal connection and function by means of wire connection. PCB is everywhere in our real life, from small and simple electronic toys to home appliances, to large devices such as cars and spacecraft. PCB plays a role in electrical interconnection in their construction. PCB can provide an embedded platform for various electronic components such as integrated chips, capacitors and resistors. Various electronic components can be well interconnected on PCB, thereby realizing the multifunctionalization and miniaturization of electrical appliances. At the same time, there are clear markings on PCB, which can provide convenience for troubleshooting various component quality problems, and also facilitate automation production, which is helpful to industrialization process.

[0003] PCB has through holes and blind holes. In many cases, the aspect ratio of the holes (the thickness of the hole to the diameter of the hole) is large (sometimes more than 10), and the wiring spacing is small (sometimes less than 0.1 mm). Therefore, the PCB copper plating solution must have good dispersing ability. The commonly used and high dispersing ability copper plating solution includes cyanide copper plating solution, pyrophosphate copper plating solution and acid sulfate copper plating solution. However, cyanide copper plating solution is a strong alkaline plating solution that can corrode PCB resin material, so it cannot be used for PCB copper plating. The pyrophosphate copper plating solution has low plating current efficiency, unstable plating solution and difficult to handle plating wastewater, so it is replaced by improved acid sulfate copper plating solution. Acid sulfate copper plating solution also has good dispersing ability and covering ability, and the cost of the plating solution is low. The plating solution is non-toxic and the plating wastewater is easy to handle. After adding additives, an ideal plating layer can be obtained. Therefore, acid sulfate copper plating has become the best choice for modern PCB plating.

[0004] In order to meet the rapid development of electronic products, PCB also develops towards high density and high integration. For example, the hole diameter of multi-layer board is getting smaller and smaller, the thickness-to-diameter ratio of through hole is getting larger and larger, and the line width of substrate is getting smaller and smaller. Therefore, higher requirements are put forward for the performance of the acid copper plating solution for printed wiring board. SUMMARY

[0005] In order to solve the above problems, the present application provides a kind of printed wiring board acidic copper plating solution and its application, which can meet the rapid development of electronic products. The content of the present application is as follows:

[0006] The first object of the present application is to provide a printed circuit board acidic copper plating solution, which comprises 100-200 g of divalent copper ions, 1.3-1.5 mL of water-soluble chloride, 5-20 mL of sulfuric acid, 0.8-1.2 g of divalent sulfide brightener, 8-12 g of polyether compound, 0.8-1.2 g of vinyl oxazole compound, and the rest is distilled water per 1 L of the acidic copper plating solution.

[0007] In order to better achieve the above technical solutions, the divalent copper ions in the printed circuit board acidic copper plating solution formula system of the present application are any one of copper sulfate, copper chloride and copper nitrate.

[0008] In order to better achieve the above technical solutions, the water-soluble chloride in the printed circuit board acidic copper plating solution formula system of the present application is any one of hydrochloric acid, sodium chloride and potassium chloride.

[0009] In order to better achieve the above technical solutions, the divalent sulfide brightener in the printed circuit board acidic copper plating solution formula system of the present application is at least one of polydithiopropyl sulfonate sodium, phenyl polydithiopropyl sulfonate sodium and thiazoline polydithiopropyl sulfonate sodium.

[0010] In order to better achieve the above technical solutions, the polyether compound in the printed circuit board acidic copper plating solution formula system of the present application is any one of hydroxyethyl cellulose, polyethylene glycol and polyoxyethylene castor oil.

[0011] In order to better achieve the above technical solutions, the vinyl oxazole compound in the printed circuit board acidic copper plating solution formula system of the present application is any one of N-vinylimidazole, 1-vinyl 1,2,4-triazole and N-1,2,3-triazole.

[0012] The second object of the present application is to provide an application of the printed circuit board acidic copper plating solution, which comprises the following steps:

[0013] Step one, plating solution preparation: take divalent copper ions, water-soluble chloride, sulfuric acid, divalent sulfide brightener, polyether compound, vinyl oxazole compound and distilled water, stir and mix, add pH adjuster, adjust pH to 3.5-4.5, and obtain the acidic copper plating solution;

[0014] Step two, PCB plating part pretreatment: wash the plating part with water, chemically remove oil, wash with hot water, acid wash, and wash with water multiple times, and obtain the pretreated plating part;

[0015] Step three, plating: immerse the pretreated plating part in the acidic copper plating solution prepared in step one, adjust the current density to 10-25 A / dm 2The copper plating part is obtained by plating at a temperature of 30-40 DEG C for 25-40 minutes.

[0016] In order to better realize the above technical scheme, the aperture of the copper plating part in the third step of the application of the printed circuit board acidic copper plating solution is 0.1-0.2 mm, the thickness-diameter ratio of the through hole is 23-25, and the substrate line width is 40-75 mu m.

[0017] Compared with the prior art, the printed circuit board acidic copper plating solution and the application thereof can achieve the following beneficial effects:

[0018] The printed circuit board acidic copper plating solution comprises divalent copper ions, water-soluble chloride, sulfuric acid, divalent sulfide brightener, polyether compound, vinyl oxazole compound and distilled water, wherein the divalent sulfide brightener, the polyether compound and the vinyl oxazole compound are used as additives of the acidic copper plating solution, the divalent sulfide brightener can increase the brightness and gloss of the plating solution, so that the copper plating layer has better surface smoothness and visual effect, the polyether compound can increase the viscosity and stability of the plating solution, improve the structural stability and chemical inertness of the plating solution, and help to reduce problems such as volatilization, oxidation and excessive consumption in the plating process, the vinyl oxazole compound can enhance the oxidation resistance and corrosion resistance of the plating solution, improve the corrosion resistance and durability of the copper plating layer, and increase the service life and reliability of the printed circuit board product, and the additives can synergistically improve the performance and characteristics of the plating solution, improve the quality and excellent degree of the copper plating layer, and provide certain technical support and advantages for the production and application of the printed circuit board. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical scheme and advantages of the present application clearer, the technical scheme of the present application will be described clearly and completely in combination with specific embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0020] Embodiment 1

[0021] In this embodiment, 1L of the printed circuit board acidic copper plating solution comprises 150g of divalent copper ions, 1.4mL of water-soluble chloride, 12.5mL of sulfuric acid, 1.0g of divalent sulfide brightener, 10g of polyether compound, 1.0g of vinyl oxazole compound, and the rest is distilled water.

[0022] Further, the divalent copper ions in the printed circuit board acidic copper plating solution formula system of the present embodiment are copper sulfate.

[0023] Further, the water-soluble chloride in the acid copper plating solution formula system of the printed circuit board of the embodiment is hydrochloric acid.

[0024] Further, the divalent sulfide brightener in the acid copper plating solution formula system of the printed circuit board of the embodiment is sodium polydithiodipropyl sulfone.

[0025] Further, the polyether compound in the acid copper plating solution formula system of the printed circuit board of the embodiment is hydroxyethyl cellulose.

[0026] Further, the vinyl oxazole compound in the acid copper plating solution formula system of the printed circuit board of the embodiment is N-vinyl imidazole.

[0027] According to the above formula system, the application of the acid copper plating solution of the printed circuit board of the embodiment includes the following steps:

[0028] Step one, plating solution preparation: take divalent copper ions, water-soluble chloride, sulfuric acid, divalent sulfide brightener, polyether compound, vinyl oxazole compound and distilled water, stir and mix, add pH adjuster, adjust pH to 4, to obtain an acid copper plating solution;

[0029] Step two, PCB plating part pretreatment: wash the plating part with water, chemically remove oil, wash with hot water, acid wash, and wash multiple times with water to obtain a pretreated plating part;

[0030] Step three, plating: immerse the pretreated plating part of step two in the acid copper plating solution of step one, adjust the current density to 17.5 A / dm 2 , the plating temperature is 35℃, and the plating time is 30min, to obtain a copper plated part.

[0031] Further, in the application of the acid copper plating solution of the printed circuit board of the embodiment, the hole diameter of the copper plated part in step three is 0.15mm, the thickness-to-diameter ratio of the through hole is 24, and the substrate line width is 60μm.

[0032] Embodiment 2

[0033] In this embodiment, 1L of the acid copper plating solution of the printed circuit board includes 100g of divalent copper ions, 1.3mL of water-soluble chloride, 5mL of sulfuric acid, 0.8g of divalent sulfide brightener, 8g of polyether compound, 0.8g of vinyl oxazole compound, and the rest is distilled water.

[0034] Further, the divalent copper ions in the acid copper plating solution formula system of the printed circuit board of the embodiment are copper chloride.

[0035] Further, the water-soluble chloride in the acid copper plating solution formula system of the printed circuit board of the embodiment is sodium chloride.

[0036] Further, the divalent sulfide brightener in the acid copper plating solution formula system of the printed circuit board of the embodiment is sodium phenylpolysulfide.

[0037] Further, the polyether compound in the acid copper plating solution formula system of the printed circuit board of the embodiment is polyethylene glycol.

[0038] Further, the vinyl oxazole compound in the acid copper plating solution formula system of the printed circuit board of the embodiment is 1-vinyl 1,2,4-triazole.

[0039] According to the above formula system, the application of the acid copper plating solution of the printed circuit board of the embodiment includes the following steps:

[0040] Step one, plating solution preparation: take divalent copper ions, water-soluble chloride, sulfuric acid, divalent sulfide brightener, polyether compound, vinyl oxazole compound and distilled water, stir and mix, add pH adjuster, adjust pH to 3.5, to obtain an acid copper plating solution;

[0041] Step two, PCB plating part pretreatment: the plating part is washed with water, chemically degreased, washed with hot water, pickled, and washed with water multiple times to obtain a pretreated plating part;

[0042] Step three, plating: the pretreated plating part of step two is immersed in the acid copper plating solution of step one, the current density is adjusted to 10 A / dm 2 , the plating temperature is 30℃, and the plating time is 25 min to obtain a copper plated part.

[0043] Further, in the application of the acid copper plating solution of the printed circuit board of the embodiment, the aperture of the copper plated part in step three is 0.1 mm, the thickness-to-diameter ratio of the through hole is 23, and the substrate line width is 40 μm.

[0044] Embodiment 3

[0045] In the embodiment, 1L of the acid copper plating solution of the printed circuit board includes 200g of divalent copper ions, 1.5mL of water-soluble chloride, 20mL of sulfuric acid, 1.2g of divalent sulfide brightener, 12g of polyether compound, 1.2g of vinyl oxazole compound, and the rest is distilled water.

[0046] Further, the divalent copper ions in the acid copper plating solution formula system of the printed circuit board of the embodiment are copper nitrate.

[0047] Further, the water-soluble chloride in the acid copper plating solution formula system of the printed circuit board of the embodiment is potassium chloride.

[0048] Further, the divalent sulfide brightener in the acid copper plating solution of the printed circuit board of the present embodiment is thiazoline-based polydithiodipropyl sulfonate sodium.

[0049] Further, the polyether compound in the acid copper plating solution of the printed circuit board of the present embodiment is polyoxyethylene castor oil.

[0050] Further, the vinyl oxazole compound in the acid copper plating solution of the printed circuit board of the present embodiment is N-1, 2, 3-triazole.

[0051] According to the above formula, the application of the acid copper plating solution of the printed circuit board of the present embodiment includes the following steps:

[0052] Step one, plating solution preparation: take divalent copper ions, water-soluble chloride, sulfuric acid, divalent sulfide brightener, polyether compound, vinyl oxazole compound and distilled water, stir and mix, add pH adjuster, adjust pH to 4.5, to obtain an acid copper plating solution;

[0053] Step two, PCB plating part pretreatment: the plating part is washed with water, chemically degreased, washed with hot water, pickled, and washed with water multiple times to obtain a pretreated plating part;

[0054] Step three, plating: the pretreated plating part of step two is immersed in the acid copper plating solution of step one, the current density is adjusted to 25 A / dm 2 , the plating temperature is 40℃, and the plating time is 40 min to obtain a copper plated part.

[0055] Further, in the application of the acid copper plating solution of the printed circuit board of the present embodiment, the hole diameter of the copper plated part in step three is 0.2 mm, the thickness-to-diameter ratio of the through hole is 25, and the substrate line width is 75 μm.

[0056] Comparative Example 1

[0057] In the present embodiment, “1.0g of divalent sulfide brightener, 10g of polyether compound, 1.0g of vinyl oxazole compound” is changed to “10g of polyether compound, 2.0g of vinyl oxazole compound”, and the rest of the operation is the same as Example 1.

[0058] Comparative Example 2

[0059] In the present embodiment, “1.0g of divalent sulfide brightener, 10g of polyether compound, 1.0g of vinyl oxazole compound” is changed to “2.0g of divalent sulfide brightener, 10g of polyether compound”, and the rest of the operation is the same as Example 1.

[0060] Comparative Example 3

[0061] In this example, "1.0 g of divalent sulfide brightener, 10 g of polyether compound, 1.0 g of vinyl oxazole compound" is changed to "12 g of polyether compound", and the rest of the operations are the same as in Example 1.

[0062] Test Example

[0063] The acidic copper plating solutions and the plated copper pieces prepared in Examples 1-3 and Comparative Examples 1-3 were subjected to performance tests, (1) the adhesion strength of the plating layer was tested by the crosshatch method; (2) the plating layer adhesion was measured on a 100 kg grade spring testing machine; (3) the plating layer toughness, and the results are shown in Table 1:

[0064] Table 1

[0065]

[0066]

[0067] The above description is merely illustrative of the application, and not intended to limit the application. Any modifications and variations that come within the spirit and scope of the application are intended to be included within the scope of the application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the application are intended to be included in the scope of the claims of the application.

Claims

1. An acid copper electroplating solution for printed wiring boards, characterized by comprising: Each 1L of the acidic copper plating solution is composed of 100-200g of divalent copper ions, 1.3-1.5mL of water-soluble chloride, 5-20mL of sulfuric acid, 0.8-1.2g of divalent sulfide brightener, 8-12g of polyether compound, 0.8-1.2g of vinyl oxazole compound, and the rest of distilled water; The divalent sulfide brightener is at least one of sodium polydithiopropyl sulfide, sodium phenyl polydithiopropyl sulfide, and sodium thiazoline polydithiopropyl sulfide; The polyether compound is any one of hydroxyethyl cellulose, polyethylene glycol, and polyoxyethylene castor oil; The vinyl oxazole compound is any one of N-vinylimidazole, 1-vinyl 1,2,4-triazole, and N-1,2,3-triazole; The copper plating solution is suitable for a copper plating piece with a hole diameter of 0.1-0.2mm, a thickness-diameter ratio of 23-25, and a substrate line width of 40-75μm.

2. The acidic copper electroplating solution for printed wiring boards according to claim 1, wherein The divalent copper ions are any one of copper sulfate, copper chloride, and copper nitrate.

3. The acidic copper electroplating solution for printed wiring boards according to claim 1, wherein The water-soluble chloride is any one of hydrochloric acid, sodium chloride, and potassium chloride.

4. Use of an acidic copper electroplating solution for printed wiring boards, characterized in that The method comprises the following steps: Step one, plating solution preparation: mix divalent copper ion compound, water-soluble chloride, sulfuric acid, divalent sulfide brightener, polyether compound, vinyl oxazole compound, and distilled water to prepare the acidic copper plating solution of claim 1, add pH adjuster to adjust the pH to 3.5-4.5 to obtain the final acidic copper plating solution; Step two, PCB plating piece pretreatment: wash the plating piece with water, chemically remove oil, wash with hot water, acid wash, and wash with water multiple times to obtain the pretreated plating piece; Step three, electroplating: the electroplated part pretreated in step two is immersed in the final acidic copper electroplating solution in step one, the current density is adjusted to 10-25 A / dm 2 , the electroplating temperature is 30-40℃, and the electroplating time is 25-40 min to obtain a copper plated part.

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