A polish and its use

Abstract

The application discloses a brightener, which comprises the following components: 5-10 g / L of sulfuric acid, 2.5-5 g / L of copper sulfate pentahydrate, 5-15 g / L of an inhibitor, 18-25 g / L of a wetting agent, 0.1-0.5 g / L of a stabilizer and 0.9-1.5 g / L of a brightener. The brightener disclosed by the application is simple to operate, safe in formula, affordable in price, applied to soft plate copper plating, free from plate bending and plate warping, good in quality and high in qualified rate.

Description

Technical Field

[0001] This invention relates to the field of C25D3 / 38, and more specifically to a gloss agent and its application. Background Technology

[0002] With the continuous advancement of modern technology, electronic products are constantly evolving towards miniaturization, convenience, and intelligence. Flexible circuit boards (FPCBs) are a crucial component in manufacturing these products. In addition to their inherent flexibility, they are highly adaptable, capable of being bent, rolled, twisted, and folded freely, changing shape arbitrarily according to spatial layout requirements. They can also move and stretch freely in three-dimensional space to achieve integrated component assembly and wire connection. Metallized through-holes or blind vias are used in FPCBs to achieve conductivity between different layers. Copper plating of through-holes is an important method for achieving through-hole metallization. However, during DC electroplating, due to the uneven current density distribution within the through-holes, it is difficult to obtain a uniform plating thickness using traditional plating solutions. Using organic additives is an effective and economical method. Therefore, developing effective, stable, and adaptable through-hole plating additives is essential.

[0003] CN107217282B discloses a high TP value flexible circuit board electroplating solution and electroplating method. The electroplating solution contains anhydrous copper sulfate; the B component is sulfuric acid, chloride, polyethylene glycol, polypropylene alcohol, etc. The total organic carbon content of the electroplating solution is low, the ductility and thermal shock reliability of the electroplated copper are high, and the TP value of the through holes of the flexible circuit board is high. CN108130564A discloses a vertical continuous electroplating high TP value acidic copper plating brightener, its preparation method and application. The acidic copper plating brightener contains a brightener, a high-temperature carrier, a leveling agent, an inhibitor, and an acid copper leveling agent. It enables the copper plating thickness inside the holes of the vertical continuous electroplating acidic copper plating of the flexible circuit board to be 1.5 to 2.5 times the copper plating thickness on the board surface, and the plated copper has good ductility and thermal shock resistance.

[0004] However, the electroplating solutions or gloss agents used in the above-mentioned flexible circuit boards have poor stability, produce many decomposition products, and have a high TOC value growth rate. Furthermore, copper plating on flexible circuit boards can easily cause board bending and warping, resulting in a high defect rate. Summary of the Invention

[0005] To address the aforementioned problems, this invention discloses a glossing agent comprising the following components: 5-10 g / L sulfuric acid, 2.5-5 g / L copper sulfate pentahydrate, 5-15 g / L inhibitor, 18-25 g / L wetting agent, 0.1-0.5 g / L stabilizer, 0.9-1.5 g / L brightener, with the balance being solvent.

[0006] In one embodiment, the sulfuric acid has a mass concentration of 40%-60%.

[0007] Preferably, the sulfuric acid has a mass concentration of 50%.

[0008] In one embodiment, the inhibitor is selected from one or more of ether inhibitors, pyridine inhibitors, alcohol inhibitors, and amide inhibitors.

[0009] Preferably, the inhibitor is an amide inhibitor.

[0010] More preferably, the amide inhibitor is N-benzyl-4-chloro-N-cyclohexylbenzamide (FPS).

[0011] In one embodiment, the wetting agent is selected from one or more of sulfonates, sulfates, alcohols, and organosilicones.

[0012] Preferably, the wetting agent is a combination of sulfonate, sulfate and alcohol in a mass ratio of (0.1-0.5):(0.3-0.5):(18-22).

[0013] More preferably, the sulfonate is sodium hydroxyethyl sulfonate; the sulfate is sodium isooctanol sulfate; and the alcohol is polyethylene glycol.

[0014] More preferably, the average molecular weight of the polyethylene glycol is 200-1000.

[0015] In one embodiment, the stabilizer is selected from one or more of pyridine benzimidazole, aminoimidazole, guanine, 6-aminopurine, thiazole, and benzoxazole.

[0016] Preferably, the stabilizer is benzoxazole.

[0017] More preferably, the stabilizer is sodium 3-(benzothiazol-2-mercapto)propanesulfonate (ZPS).

[0018] In one embodiment, the brightener is selected from one or more of thiazoles, sulfonates, sulfonamides, and aldehydes.

[0019] Preferably, the brightening agent is a combination of thiazole and sulfonate in a mass ratio of (0.3-0.5):(0.6-1).

[0020] More preferably, the thiazole is tetrahydrothiazolethione; and the sulfonate is sodium polydithiopropanesulfonate.

[0021] The brightener is thiazole, especially tetrahydrothiazolium thione, which has excellent adsorption properties, allowing metal ions to deposit in areas with lower current density. Sulfonates can complex with copper ions and also have adsorption properties on the copper electrode surface. The combined effect of these two components ensures an orderly metal ion deposition process, improving the mechanical properties of the coating. Adding amide inhibitors and controlling the wetting agent to be a combination of sulfonates, sulfates, and alcohols in a mass ratio of (0.1-0.5):(0.3-0.5):(18-22) can further improve the coating's ductility and increase the TP value. This is likely because, in the formulation system of this invention, amide inhibitors have a strong inhibitory effect, strongly suppressing deposition on the surface. Under the action of the wetting agent, deposition is preferentially completed at the through-holes on the flexible plate. Furthermore, adding a small amount of sulfuric acid, copper sulfate pentahydrate, and a stabilizer to the brightener can improve its stability, reduce decomposition products, and decrease the TOC value growth rate.

[0022] In one embodiment, the solvent is deionized water.

[0023] Another aspect of the present invention discloses the application of the gloss agent, characterized in that it is applied to copper plating of flexible circuit boards.

[0024] The concentration of the brightener added to the electroplating solution is 4-6 ml / L.

[0025] Beneficial effects

[0026] 1. The brighteners are thiazole and sulfonate. The two work together to make the metal ion deposition process orderly and improve the mechanical properties of the coating.

[0027] 2. Adding amide inhibitors and controlling the wetting agent to be a combination of sulfonates, sulfates and alcohols in a mass ratio of (0.1-0.5):(0.3-0.5):(18-22) can further improve the ductility of the coating and increase the TP value.

[0028] 3. Adding a small amount of sulfuric acid, copper sulfate pentahydrate, and stabilizer to the brightener can improve its stability, reduce decomposition products, and decrease the TOC value growth rate.

[0029] 4. The brightener disclosed in this invention is simple to operate, has a safe formula, and is affordable. When applied to copper plating of flexible circuit boards, it does not cause board bending or warping, resulting in good quality and a high pass rate. Detailed Implementation

[0030] Example 1

[0031] Example 1 discloses a glossing agent with the following components: 5 g / L sulfuric acid, 5 g / L copper sulfate pentahydrate, 5 g / L inhibitor, 18 g / L wetting agent, 0.1 g / L stabilizer, 0.9 g / L brightener, and the balance being deionized water.

[0032] The sulfuric acid has a mass concentration of 50%.

[0033] The inhibitor is N-benzyl-4-chloro-N-cyclohexylbenzamide (FPS).

[0034] The wetting agent is a combination of sulfonates, sulfates, and alcohols in a mass ratio of 0.1:0.5:18.

[0035] The sulfonate is sodium hydroxyethyl sulfonate; the sulfate is sodium isooctanol sulfate; and the alcohol is polyethylene glycol.

[0036] The polyethylene glycol has an average molecular weight of 400 and is commercially available.

[0037] The stabilizer is sodium 3-(benzothiazol-2-mercapto)propanesulfonate (ZPS).

[0038] The brightening agent is a combination of thiazole and sulfonate in a mass ratio of 0.3:1.

[0039] The thiazole is tetrahydrothiazolethion (CAS No.: 96-53-7); the sulfonate is sodium polydisulfide dipropane sulfonate (molecular formula: C6H). 12 Na2O6S4).

[0040] This embodiment 1 also discloses the application of the gloss agent, which is used in copper plating of flexible circuit boards.

[0041] The concentration of the brightener added to the electroplating solution is 6 ml / L.

[0042] Example 2

[0043] Example 2 discloses a gloss agent with the following components: 10 g / L sulfuric acid, 2.5 g / L copper sulfate pentahydrate, 15 g / L inhibitor, 25 g / L wetting agent, 0.5 g / L stabilizer, and 1.5 g / L brightener.

[0044] The sulfuric acid has a mass concentration of 50%.

[0045] The inhibitor is N-benzyl-4-chloro-N-cyclohexylbenzamide (FPS).

[0046] The wetting agent is a combination of sulfonates, sulfates, and alcohols in a mass ratio of 0.5:0.3:22.

[0047] The sulfonate is sodium hydroxyethyl sulfonate; the sulfate is sodium isooctanol sulfate; and the alcohol is polyethylene glycol.

[0048] The polyethylene glycol has an average molecular weight of 400 and is commercially available.

[0049] The stabilizer is sodium 3-(benzothiazol-2-mercapto)propanesulfonate (ZPS).

[0050] The brightening agent is a combination of thiazole and sulfonate in a mass ratio of 0.5:0.6.

[0051] The thiazole is tetrahydrothiazolethion (CAS No.: 96-53-7); the sulfonate is sodium polydisulfide dipropane sulfonate (molecular formula: C6H). 12 Na2O6S4).

[0052] This embodiment 2 discloses, in another aspect, the application of the gloss agent, in the copper plating of flexible circuit boards.

[0053] The concentration of the brightener added to the electroplating solution is 4 ml / L.

[0054] Example 3

[0055] Example 3 discloses a gloss agent with the following components: 6.5 g / L sulfuric acid, 3.5 g / L copper sulfate pentahydrate, 12.8 g / L inhibitor, 19.3 g / L wetting agent, 0.3 g / L stabilizer, and 1.2 g / L brightener.

[0056] The sulfuric acid has a mass concentration of 50%.

[0057] The inhibitor is N-benzyl-4-chloro-N-cyclohexylbenzamide (FPS).

[0058] The wetting agent is a combination of sulfonates, sulfates, and alcohols in a mass ratio of 0.2:0.4:20.

[0059] The sulfonate is sodium hydroxyethyl sulfonate; the sulfate is sodium isooctanol sulfate; and the alcohol is polyethylene glycol.

[0060] The polyethylene glycol has an average molecular weight of 600 and is commercially available.

[0061] The stabilizer is sodium 3-(benzothiazol-2-mercapto)propanesulfonate (ZPS).

[0062] The brightener is a combination of thiazole and sulfonate in a mass ratio of 0.4:0.7.

[0063] The thiazole is tetrahydrothiazolethion (CAS No.: 96-53-7); the sulfonate is sodium polydisulfide dipropane sulfonate (molecular formula: C6H). 12Na2O6S4).

[0064] This embodiment 3 discloses, in another aspect, the application of the gloss agent, in the copper plating of flexible circuit boards.

[0065] The concentration of the brightener added to the electroplating solution is 5 ml / L.

[0066] Example 4

[0067] The difference between Example 4 and Example 3 is that the components are: 6.5 g / L sulfuric acid, 3.5 g / L copper sulfate pentahydrate, 19 g / L inhibitor, 19.3 g / L wetting agent, 0.3 g / L stabilizer, and 2 g / L brightener.

[0068] Example 5

[0069] The difference between Example 5 and Example 3 is that the brightening agent is a combination of thiazole and sulfonate in a mass ratio of 10:0.1.

[0070] Example 6

[0071] The difference between Example 6 and Example 3 is that the wetting agent is a combination of sulfonate, sulfate and alcohol in a mass ratio of 22:0.3:0.5.

[0072] Example 7

[0073] The difference between Example 7 and Example 3 is that the brightening agent is sodium polydithiodipropane sulfonate (molecular formula: C6H). 12 Sodium Na2O6S4 and N,N-dimethyldithiocarbamate propanesulfonate, in a mass ratio of 0.5:0.6.

[0074] Performance testing

[0075] The flexible circuit board was electroplated using the gloss agent prepared in Examples 1-7 above, following conventional methods in the art. The electroplating solution used was a high-acid, low-copper plating solution containing sulfuric acid: 180-220 g / L, copper ions: 60-100 g / L, and chloride ions: 40-80 mg / L. The specific electroplating process parameters were: current density: 1-4 ASD, and plating solution temperature: 22±2℃.

[0076] During the performance testing of this invention, the sulfuric acid concentration was 200 g / L, the copper ion concentration was 80 g / L, and the chloride ion concentration was 60 mg / L. The specific electroplating process parameters were: current density: 2 ASD, and plating solution temperature: 22℃.

[0077] 1. Grind and slice the plated flexible circuit board and observe the deep plating capability (Throwing Power, or TP value for short = hole copper thickness / surface copper thickness) under a metallographic microscope.

[0078] 2. Ductility test: According to the standard of IPC-TM-6502.4.18.1A, a sample with a length of 150 mm and a width of 13 mm (copper thickness of 50-60 μm) was taken, baked at 125℃±5℃ for 6 hours, cooled to room temperature, and stretched at a rate of 20 mm / min with a gauge length of 50 mm.

[0079] The formula for calculating elongation is as follows:

[0080] Elongation = (Tear length - Original standard length) / Original standard length × 100%

[0081] Tensile strength calculation method:

[0082] 1. Weigh the sample with an accuracy of 0.0001g and record the weight.

[0083] 2: Calculation: (The mass of the electrolytic copper foil is 8.909 g / cm³) 3 )

[0084] Average cross-sectional area = Sample weight / (Sample length × Copper foil density)

[0085] Tensile strength (MPa) = Load force of the broken specimen / Average cross-sectional area

[0086]

[0087]

Claims

1. A gloss agent, characterized in that, The product comprises the following components: 5-10 g / L sulfuric acid, 2.5-5 g / L copper sulfate pentahydrate, 5-15 g / L inhibitor, 18-25 g / L wetting agent, 0.1-0.5 g / L stabilizer, 0.9-1.5 g / L brightener, with the balance being solvent; the inhibitor is N-benzyl-4-chloro-N-cyclohexylbenzamide; the wetting agent is a combination of sulfonate, sulfate, and alcohol in a mass ratio of (0.1-0.5):(0.3-0.5):(18-22), wherein the sulfonate is sodium hydroxyethyl sulfonate; the sulfate is sodium isooctyl sulfate; the alcohol is polyethylene glycol; the stabilizer is sodium 3-(benzothiazol-2-mercapto)propane sulfonate; and the brightener is a combination of tetrahydrothiazolium thione and sodium polydithiopropane sulfonate in a mass ratio of (0.3-0.5):(0.6-1).

2. The gloss agent according to claim 1, characterized in that, The sulfuric acid has a mass concentration of 40%-60%.

3. The gloss agent according to claim 1, characterized in that, The average molecular weight of the polyethylene glycol is 200-1000.

4. An application of a gloss agent according to any one of claims 1-3, characterized in that, It is used for copper plating on flexible printed circuit boards.

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