Solution, preparation method of printed circuit board, printed circuit board and electronic equipment

Abstract

The invention relates to the technical field of printed circuit boards, in particular to a solution, a preparation method of a printed circuit board, the printed circuit board and electronic equipment. The solution comprises: a first compound selected from at least one of nitrogen-containing carboxylic acid and salts thereof, and water-soluble amine compounds; a second compound selected from at least one of hydroxyl-containing carboxylic acids and salts thereof; and a third compound selected from hypophosphite. According to the solution provided by some embodiments of the invention, through the synergistic effect of the first compound, the second compound and the third compound, small molecules and molecules with low polymerization degree in the ink are selectively dissolved out in advance on the premise of not damaging the integrity of the main body structure of the solder resist ink; and the dissolution amount of the solder resist ink in the chemical plating bath solution in the subsequent chemical plating treatment process is reduced, and the bath solution is effectively protected from being polluted, so that the reduction of the deposition rate of a chemical plating layer is slowed down, the uniformity of the thickness of the plating layer is ensured, the quality defects such as skip plating, gold surface color difference and nickel corrosion are reduced, and the product yield is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of printed circuit boards, and in particular to a solution, a printed circuit board preparation method, a printed circuit board and an electronic device. BACKGROUND

[0002] A printed circuit board (PCB) is a core basic component for carrying electronic device signal transmission, signal transceiving and power supply.

[0003] In the prior art, a chemical nickel-gold plating or a chemical nickel-palladium-gold plating is used to perform surface treatment on metal wiring on a PCB, so as to provide excellent solderability, conductivity, wireability and heat dissipation for the PCB.

[0004] However, such a surface treatment process is highly sensitive to process conditions, and is particularly susceptible to the influence of solder resist ink. Due to the complex composition of the solder resist ink, the quality difference between different manufacturers, insufficient curing during the solder resist process and other reasons, the solder resist ink is prone to leaching in a high-temperature and high-chemical-activity chemical plating bath, causing contamination of the bath, and thus causing various quality problems, such as a significant decrease in the deposition rate of the chemical plating layer, color difference of the gold surface due to uneven thickness, plating leakage, plating penetration, nickel corrosion and abnormal adhesion, which seriously affect the product yield. SUMMARY

[0005] Therefore, it is necessary to provide a solution, a printed circuit board preparation method, a printed circuit board and an electronic device to reduce the leaching of solder resist ink in a chemical plating bath, so as to protect the bath from contamination and improve the product yield.

[0006] In a first aspect, the present application provides a solution, which comprises: a first compound selected from at least one of a nitrogen-containing carboxylic acid and a salt thereof and a water-soluble amine compound; a second compound selected from at least one of a hydroxyl-containing carboxylic acid and a salt thereof; and a third compound selected from a hypophosphite.

[0007] In some embodiments, the nitrogen-containing carboxylic acid is selected from at least one of ethylenediaminetetraacetic acid, hydroxyethylethylenediaminetriacetic acid, dihydroxyethylenediaminediacetic acid, propylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, triethylenetetraminehexaacetic acid, glycine, iminodiacetic acid, hydroxyethyliminodiacetic acid, nitrilotriacetic acid and nitrilotripropionic acid.

[0008] In some embodiments, the water-soluble amine compound is selected from at least one of monoethanolamine, diethanolamine, triethanolamine, ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenohexamine, methylamine and dimethylamine.

[0009] In some embodiments, the hydroxyl-containing carboxylic acid is selected from at least one of glycolic acid, diglycolic acid, glyceric acid, tartronic acid, lactic acid, malic acid, citric acid, tartaric acid, gluconic acid, glucoheptonic acid, alpha-hydroxyglutaric acid, beta-hydroxyglutaric acid, and beta-hydroxybutyric acid.

[0010] In some embodiments, the hypophosphorous acid salt is selected from at least one of sodium hypophosphite, potassium hypophosphite, and ammonium hypophosphite.

[0011] In some embodiments, the solution satisfies at least one of the following conditions: (1) the concentration of the first compound is 0.01 mol / L to 2 mol / L; (2) the concentration of the second compound is 0.01 mol / L to 2 mol / L; (3) the concentration of the third compound is 0.01 mol / L to 1 mol / L; (4) the pH value of the solution is 4 to 9; and (5) the solvent of the solution comprises water.

[0012] In a second aspect of the present application, a preparation method of a printed circuit board is provided, and the preparation method comprises the following steps: performing pre-dissolution treatment on a solder resist ink on a surface of a printed circuit board substrate by using the solution provided in the first aspect; and performing chemical plating treatment on the surface of the printed circuit board substrate after the pre-dissolution treatment.

[0013] In some embodiments, the pre-dissolution treatment satisfies at least one of the following conditions: (1) the temperature of the pre-dissolution treatment is 30°C to 90°C; (2) the time of the pre-dissolution treatment is 2 min to 60 min; and (3) the pre-dissolution treatment comprises immersion treatment.

[0014] In a third aspect of the present application, a printed circuit board is provided, and the printed circuit board is prepared by using the preparation method of the printed circuit board provided in the second aspect.

[0015] In a fourth aspect of the present application, an electronic device is provided, and the electronic device comprises the printed circuit board provided in the third aspect.

[0016] Compared with the conventional technology, the present application has at least the following beneficial effects:

[0017] The solution provided in some embodiments of the present application can selectively dissolve out small molecules and low-polymerization-degree molecules in the solder resist ink in advance under the premise of not damaging the integrity of the main structure of the solder resist ink, by the synergistic effect of the first compound, the second compound, and the third compound, so as to reduce the dissolution amount of the solder resist ink in the chemical plating bath in the subsequent chemical plating process, effectively protect the bath from pollution, slow down the decrease of the chemical plating layer deposition rate, ensure the uniformity of the plating layer thickness, reduce quality defects such as plating leakage, gold surface color difference, and nickel corrosion, and improve product yield. DETAILED DESCRIPTION

[0018] Reference will now be made in detail to the embodiments of the application, one or more examples of which are described hereinbelow. Each example is provided by way of explanation of the application, not limitation of the application. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present application without departing from the scope or spirit of the application. For instance, features illustrated or described as part of one embodiment, can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present application cover modifications and variations of this application provided they come within the scope of the appended claims and their equivalents.

[0019] It is therefore intended that the application cover all such modifications and variations of this application provided they come within the scope of the appended claims and their equivalents. Other objects, features and aspects of the present application are disclosed in or are apparent from the following detailed description of the application. It is to be understood by the foregoing description that the form of the application herein disclosed is to be considered only insofar as representative of the principles of the application. The description together with the claims and drawings is to be regarded in an illustrative rather than a restrictive sense.

[0020] In the present application, the technical features described in an open way include both the closed technical solution consisting of the listed features and the open technical solution containing the listed features.

[0021] In the present application, when referring to a numerical interval, unless otherwise specified, the numerical interval is considered to be continuous and includes the minimum and maximum values of the range and every value between the minimum and maximum values. Further, when the range refers to integers, every integer between the minimum and maximum values of the range is included. In addition, when multiple ranges are provided to describe a feature or a characteristic, the ranges can be combined. In other words, unless otherwise specified, all ranges disclosed herein are to be understood to include any and all sub-ranges subsumed therein.

[0022] If not specifically stated, all embodiments and optional embodiments of the present application can be combined with each other to form new technical solutions.

[0023] If not specifically stated, all technical features and optional technical features of the present application can be combined with each other to form new technical solutions.

[0024] If not specifically stated, all steps of the present application can be performed in sequence or randomly, and preferably in sequence. For example, the method comprises steps (a) and (b), indicating that the method can comprise steps (a) and (b) performed in sequence, or steps (b) and (a) performed in sequence. For example, it is mentioned that the method can further comprise step (c), indicating that step (c) can be added to the method in any order, for example, the method can comprise steps (a), (b) and (c), or steps (a), (c) and (b), or steps (c), (a) and (b), etc.

[0025] As used herein, "comprising" and "including" are meant to be open ended, and also mean "consisting essentially of" or "consisting of" unless otherwise noted. For example, "comprising" and "including" can mean that other components can also be included or can consist only of the listed components.

[0026] As used herein, "solder resist ink" refers to a protective coating used in the soldering process of printed circuit boards, which forms an insulating protective layer in the non-soldering area to prevent short circuits and oxidation, protecting the stability and reliability of the circuit. The composition of solder resist ink is complex, mainly composed of resins (such as epoxy resin, polyurethane, acrylic resin), hardening agents and fillers, dyes and ultraviolet reactive substances.

[0027] As used herein, "electroless plating treatment" refers to a surface treatment process that utilizes the principle of autocatalysis to deposit metal or alloy plating on the surface of the body. The electroless plating bath generally has high temperature and high chemical activity. For example, the temperature of nickel bath and gold bath is generally 70-90°C, the temperature of palladium bath is generally 40-60°C, and the nickel bath, palladium bath and gold bath generally contain a large amount of organic acid (salt) and inorganic salt.

[0028] In a first aspect of the present application, a solution is provided, which includes a first compound, a second compound and a third compound. The first compound is selected from at least one of nitrogen-containing carboxylic acid and its salt and water-soluble amine compound. The second compound is selected from at least one of hydroxyl-containing carboxylic acid and its salt. The third compound is selected from hypophosphite.

[0029] The solution provided by some embodiments of the present application can selectively dissolve small molecules and low-polymerization-degree molecules in the solder resist ink that are not fully cured in advance, without damaging the integrity of the main structure of the solder resist ink, thereby reducing the amount of solder resist ink dissolved in the electroless plating bath in the subsequent electroless plating process, effectively protecting the bath from contamination, slowing down the decrease in the deposition rate of the electroless plating layer, ensuring the uniformity of the plating layer thickness, reducing quality defects such as plating leakage, color difference on the gold surface and nickel corrosion, and improving product yield.

[0030] The first compound is selected from at least one of nitrogen-containing carboxylic acid and its salt and water-soluble amine compound. The first compound plays a complexing role, and the nitrogen atom in its molecular structure has a lone pair of electrons, which can interact strongly with small polar molecules on the surface of the solder resist ink, causing them to separate from the surface of the solder resist ink and enter the solution. The nitrogen-containing carboxylic acid and its salt have amine and carboxyl groups in their molecular structure, contain polydentate coordination structures, and have stronger complexing ability. In addition, the nitrogen-containing carboxylic acid and its salt are highly similar in chemical structure to some small molecules (such as polyurethane fragments), and can promote their dissolution into the solution by the principle of "like dissolves like"; the water-soluble amine compound is alkaline in aqueous solution, which helps to promote the dissolution of acidic small molecules.

[0031] The second compound is selected from at least one of hydroxyl-containing carboxylic acids and salts thereof. The second compound plays a role of solubilization, and has a molecular structure containing a hydroxyl group and a carboxyl group, which is highly similar in chemical structure to a small molecule of a resin (such as an epoxy resin fragment, a polyurethane fragment, an acrylic acid fragment) in the solder resist ink, and can significantly improve the solution capacity of the solution to the already stripped contaminants by using the principle of "like dissolves like" to prevent the re-deposition of the contaminants.

[0032] The third compound is selected from a hypophosphite salt. The third compound plays a role of stabilization, and has a mild reducing property, which can prevent the organic matter already dissolved in the solution from being further oxidized, and inhibit other chemical side reactions, thereby indirectly improving the integrity of the main structure of the solder resist ink.

[0033] In some embodiments, the nitrogen-containing carboxylic acid is selected from at least one of ethylenediaminetetraacetic acid, hydroxyethylethylenediaminetriacetic acid, dihydroxyethylenediaminediacetic acid, propylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, triethylenetetraminehexaacetic acid, glycine, iminodiacetic acid, hydroxyethyliminodiacetic acid, nitrilotriacetic acid, and nitrilotripropionic acid.

[0034] Further, the nitrogen-containing carboxylic acid is selected from ethylenediaminetetraacetic acid. Thus, ethylenediaminetetraacetic acid, as a polydentate ligand, has a molecular structure containing multiple nitrogen atoms and carboxyl groups, which can provide multiple coordination sites and has a strong complexing ability, thereby being able to efficiently capture and strip polar small molecule contaminants on the surface of the solder resist ink, and in addition, it is low in cost and suitable for industrial applications.

[0035] In some embodiments, the water-soluble amine compound is selected from at least one of monoethanolamine, diethanolamine, triethanolamine, ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentaamine, pentaethylenehexamine, methylamine, and dimethylamine.

[0036] Further, the water-soluble amine compound is selected from ethylenediamine. Thus, ethylenediamine has good complexing ability, and at the same time, it exhibits strong alkalinity in an aqueous solution, which is helpful to promote the dissolution of acidic small molecules.

[0037] In some embodiments, the hydroxyl-containing carboxylic acid is selected from at least one of glycolic acid, diglycolic acid, glyceric acid, tartronic acid, lactic acid, malic acid, citric acid, tartaric acid, gluconic acid, glucoheptonic acid, a-hydroxyglutaric acid, β-hydroxyglutaric acid, and β-hydroxybutyric acid.

[0038] Further, the hydroxyl-containing carboxylic acid is selected from lactic acid. Thus, the lactic acid has both hydroxyl and carboxyl groups in its molecular structure, which has structural similarity with the functional groups of the small molecules (e.g., acrylic resin fragments) dissolved from the solder resist ink, and according to the principle of similar dissolves similar, the lactic acid can significantly improve the solution's ability to dissolve the already stripped contaminants and prevent their redeposition. In addition, it is low in cost and suitable for industrial applications. In some embodiments, the hypophosphorous acid salt is selected from at least one of sodium hypophosphite, potassium hypophosphite, and ammonium hypophosphite.

[0039] In some embodiments, the concentration of the first compound is 0.01 mol / L to 2 mol / L. Illustratively, the concentration of the first compound can be, but is not limited to, 0.01 mol / L, 0.05 mol / L, 0.1 mol / L, 0.5 mol / L, 1 mol / L, 1.5 mol / L, or 2 mol / L.

[0040] Further, the concentration of the first compound is 0.01 mol / L to 1 mol / L.

[0041] In some embodiments, the concentration of the second compound is 0.01 mol / L to 2 mol / L. Illustratively, the concentration of the second compound can be, but is not limited to, 0.01 mol / L, 0.05 mol / L, 0.1 mol / L, 0.5 mol / L, 1 mol / L, 1.5 mol / L, or 2 mol / L.

[0042] Further, the concentration of the second compound is 0.01 mol / L to 1 mol / L.

[0043] In some embodiments, the concentration of the third compound is 0.01 mol / L to 1 mol / L. Illustratively, the concentration of the third compound can be, but is not limited to, 0.01 mol / L, 0.05 mol / L, 0.1 mol / L, 0.5 mol / L, or 1 mol / L.

[0044] Further, the concentration of the third compound is 0.05 mol / L to 0.5 mol / L.

[0045] Specifically, the concentrations of the first compound, the second compound, and the third compound are set within the above ranges, which can not only ensure that each component can effectively play its role in the solution and improve the pre-dissolution efficiency of the small molecules and oligomeric compounds of the solder resist ink, but also can ensure the integrity of the main structure of the solder resist ink as much as possible.

[0046] In some embodiments, the pH of the solution is 4-9. Illustratively, the pH of the solution can be, but is not limited to, 4, 5, 6, 7, 8, 9. When adjusting the pH, an acid or a base can be used for adjustment, such as hydrochloric acid, sulfuric acid, ammonia, sodium hydroxide, potassium hydroxide, etc. Within the above pH range, the components in the solution can play their roles, and a relatively mild chemical environment can be provided to ensure the integrity of the main structure of the solder resist ink.

[0047] Further, the pH of the solution is 7. The neutral condition can maximize the protection of the main structure of the solder resist ink.

[0048] In some embodiments, the solvent of the solution comprises water.

[0049] In a second aspect of the present application, a preparation method of a printed circuit board is provided, which comprises the following steps:

[0050] S1, using the solution provided in the first aspect to perform a pre-dissolution treatment on the solder resist ink on the surface of the printed circuit board substrate.

[0051] S2, performing a chemical plating treatment on the surface of the printed circuit board substrate after the pre-dissolution treatment.

[0052] The preparation method of the printed circuit board provided in some embodiments of the present application uses the solution provided in the first aspect to perform a pre-dissolution treatment on the solder resist ink on the surface of the printed circuit board substrate. Through the synergistic effect of the first compound, the second compound, and the third compound, small molecules that are not sufficiently cured and molecules with low polymerization degree in the ink can be selectively dissolved out in advance without damaging the integrity of the main structure of the solder resist ink, the amount of the solder resist ink dissolved in the chemical plating bath during the subsequent chemical plating treatment is reduced, the bath is effectively protected from pollution, the decrease in the deposition rate of the chemical plating layer is slowed down, the uniformity of the plating layer thickness is ensured, quality defects such as plating leakage, color difference of gold surface, and nickel corrosion are reduced, and the product yield of the printed circuit board is improved.

[0053] In some embodiments, the temperature of the pre-dissolution treatment is 30-90°C. Illustratively, the temperature of the pre-dissolution treatment can be, but is not limited to, 30°C, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C.

[0054] In some embodiments, the time of the pre-dissolution treatment is 2-60 min. Illustratively, the time of the pre-dissolution treatment can be, but is not limited to, 2 min, 10 min, 20 min, 30 min, 40 min, 50 min, 60 min.

[0055] In some embodiments, the pre-dissolution treatment is performed in the form of immersion treatment.

[0056] In a third aspect, the present application provides a printed circuit board, which is prepared by the method for preparing a printed circuit board according to the second aspect.

[0057] In a fourth aspect, the present application provides an electronic device, which comprises the printed circuit board according to the third aspect.

[0058] The electronic device in the embodiments of the present application can be a mobile phone, a tablet computer, a notebook computer, a smart bracelet, a smart watch, a smart helmet, smart glasses, a smart television, etc. The electronic device can also be a cellular phone, a cordless phone, a session initiation protocol phone, a wireless local loop station, a personal digital assistant, a handheld device with wireless communication function, a computing device or other processing device connected to a wireless modem, a vehicle-mounted device, an electronic device in a 5G network or an electronic device in a future evolved universal terrestrial radio access network, etc. The embodiments of the present application are not limited thereto.

[0059] The present application will be further described below in combination with specific examples and comparative examples.

[0060] Unless otherwise specified, the techniques or conditions in the examples are carried out according to the techniques or conditions described in the literature in the art or according to the product instructions. Unless otherwise specified, the reagents or instruments used are all conventional products that can be obtained commercially.

[0061] Example 1

[0062] Solution:

[0063] An appropriate amount of deionized water was taken, and then disodium ethylenediaminetetraacetate (EDTA·2Na), citric acid and sodium hypophosphite were sequentially added to prepare a solution, wherein the concentration of EDTA·2Na in the solution was 0.01 mol / L, the concentration of citric acid in the solution was 0.5 mol / L, and the concentration of sodium hypophosphite in the solution was 0.2 mol / L. Then, sodium hydroxide was used to adjust the pH value of the solution to 8.

[0064] Printed circuit board:

[0065] The process steps are specifically as follows: pre-dissolution, water washing, oil removal, water washing, oil removal, water washing, micro-etching, water washing, pre-dipping, activation, water washing, nickel plating, water washing, gold plating, water washing and blow drying. The water washing is 2 times, and deionized water is used, with each water washing being soaked for 1 min, and the tank volume being 2 L.

[0066] (1) Pre-dissolution: the printed circuit board substrate was immersed in the above-mentioned solution for soaking treatment at 70℃ for 60 min.

[0067] (2) De-oiling: immerse the printed circuit board substrate in TS-Acid clean 6189 de- oiling agent from Guangdong Dongshuo Technology Co., Ltd. and treat at 35°C for 5 min.

[0068] (3) Micro-etching: immerse the printed circuit board substrate in a micro-etching agent consisting of 100 g / L sodium persulfate and 2% (v / v) sulfuric acid and treat at 30°C for 2 min.

[0069] (4) Pre-dipping: immerse the printed circuit board substrate in a 1% sulfuric acid solution and treat at room temperature for 2 min.

[0070] (5) Activation: immerse the printed circuit board substrate in TS-Activator LA activator from Guangdong Dongshuo Technology Co., Ltd. and treat at 22°C for 2 min.

[0071] (6) Electroless nickel plating: immerse the printed circuit board substrate in Ni5183LMP series plating solution from Guangdong Dongshuo Technology Co., Ltd. and treat at 82°C for 25 min.

[0072] (7) Electroless gold plating: immerse the printed circuit board substrate in Au5187 series plating solution from Guangdong Dongshuo Technology Co., Ltd. and treat at 83°C for 8 min to prepare the printed circuit board.

[0073] (8) Blow-drying: use an air gun to blow-dry at a temperature of about 65°C.

[0074] Example 2

[0075] The solution and the method for preparing the printed circuit board in this example are basically the same as in Example 1, except that:

[0076] In the solution, the first compound is replaced by glycine and the second compound is replaced by lactic acid, wherein the concentration of glycine in the solution is 0.7 mol / L and the concentration of lactic acid in the solution is 0.01 mol / L; potassium hydroxide is used to adjust the pH value of the solution to 9.

[0077] Example 3

[0078] The solution and the method for preparing the printed circuit board in this example are basically the same as in Example 1, except that:

[0079] In the solution, the first compound is replaced by trisodium hydroxyethylethylenediaminetriacetate and diethylenetriamine and the second compound is replaced by lactic acid, wherein the concentration of trisodium hydroxyethylethylenediaminetriacetate in the solution is 0.3 mol / L, the concentration of diethylenetriamine in the solution is 0.3 mol / L, and the concentration of lactic acid in the solution is 0.3 mol / L; sulfuric acid is used to adjust the pH value of the solution to 7.

[0080] Example 4

[0081] The solution and the preparation method of the printed circuit board in this embodiment are basically the same as those in Embodiment 1, except that:

[0082] In the solution, the first compound is replaced by glycine and ethylenediamine, and the second compound is replaced by lactic acid, wherein the concentration of glycine in the solution is 0.05 mol / L, the concentration of ethylenediamine in the solution is 0.05 mol / L, and the concentration of lactic acid in the solution is 1 mol / L; the pH value of the solution is adjusted to 7 by using ammonia water.

[0083] In step (1), the temperature of the pre-dissolution treatment is 60°C.

[0084] Embodiment 5

[0085] The solution and the preparation method of the printed circuit board in this embodiment are basically the same as those in Embodiment 1, except that:

[0086] In the solution, the first compound is replaced by ethylenediamine, and the second compound is replaced by lactic acid, wherein the concentration of ethylenediamine in the solution is 0.25 mol / L, and the concentration of lactic acid in the solution is 0.5 mol / L; the pH value of the solution is adjusted to 7 by using sodium hydroxide.

[0087] In step (1), the temperature of the pre-dissolution treatment is 60°C.

[0088] Embodiment 6

[0089] The solution and the preparation method of the printed circuit board in this embodiment are basically the same as those in Embodiment 1, except that:

[0090] In the solution, the first compound is replaced by triethanolamine, and the second compound is replaced by malic acid, wherein the concentration of triethanolamine in the solution is 0.2 mol / L, and the concentration of malic acid in the solution is 0.4 mol / L; the pH value of the solution is adjusted to 4 by using sodium hydroxide.

[0091] Embodiment 7

[0092] The solution and the preparation method of the printed circuit board in this embodiment are basically the same as those in Embodiment 1, except that:

[0093] In the solution, the first compound is replaced by triethylenetetramine, wherein the concentration of triethylenetetramine in the solution is 0.15 mol / L, and the concentration of citric acid in the solution is 0.5 mol / L; the pH value of the solution is adjusted to 7 by using sodium hydroxide.

[0094] In step (1), the temperature of the pre-dissolution treatment is 60°C.

[0095] Embodiment 8

[0096] The solution and the preparation method of the printed circuit board in this example are basically the same as those in Example 1, except that:

[0097] In the solution, the second compound is replaced by malic acid, and the third compound is replaced by potassium hypophosphite, wherein the concentration of EDTA 2Na in the solution is 0.2 mol / L, the concentration of malic acid in the solution is 0.4 mol / L, and the concentration of potassium hypophosphite in the solution is 0.2 mol / L; sodium hydroxide is used to adjust the pH value of the solution to 7.

[0098] Example 9

[0099] The solution and the preparation method of the printed circuit board in this example are basically the same as those in Example 1, except that:

[0100] In the solution, the first compound is replaced by glycine, the second compound is replaced by glycolic acid, and the third compound is replaced by potassium hypophosphite, wherein the concentration of glycine in the solution is 0.7 mol / L, the concentration of glycolic acid in the solution is 0.7 mol / L, and the concentration of potassium hypophosphite in the solution is 0.2 mol / L; sodium hydroxide is used to adjust the pH value of the solution to 7.

[0101] In step (1), the temperature of the pre-dissolution treatment is 90°C, and the time of the pre-dissolution treatment is 2 min.

[0102] Example 10

[0103] The solution and the preparation method of the printed circuit board in this example are basically the same as those in Example 1, except that:

[0104] In the solution, the first compound is replaced by ethylenediamine, and the second compound is replaced by lactic acid, wherein the concentration of ethylenediamine in the solution is 0.2 mol / L, and the concentration of lactic acid in the solution is 0.3 mol / L; sulfuric acid is used to adjust the pH value of the solution to 7.

[0105] In step (1), the temperature of the pre-dissolution treatment is 60°C.

[0106] Comparative Example 1

[0107] The solution and the preparation method of the printed circuit board in this example are basically the same as those in Example 10, except that:

[0108] The solution does not contain the third compound sodium hypophosphite; sodium hydroxide is used to adjust the pH value of the solution to 7.

[0109] Comparative Example 2

[0110] The solution and the preparation method of the printed circuit board in this example are basically the same as those in Example 10, except that:

[0111] The solution does not contain the first compound ethylenediamine; sodium hydroxide is used to adjust the pH value of the solution to 7.

[0112] Comparative Example 3

[0113] The solution and the printed circuit board in the present comparative example are prepared by substantially the same method as in Example 10, except that:

[0114] The solution does not contain lactic acid.

[0115] Comparative Example 4

[0116] The solution and the printed circuit board in the present comparative example are prepared by substantially the same method as in Example 10, except that:

[0117] The concentration of ethylenediamine in the solution is 0.005 mol / L; sodium hydroxide is used to adjust the pH value of the solution to 7.

[0118] Comparative Example 5

[0119] The solution and the printed circuit board in the present comparative example are prepared by substantially the same method as in Example 10, except that:

[0120] The solution does not contain the first compound ethylenediamine, and malonic acid is added, wherein the concentration of malonic acid in the solution is 0.2 mol / L; sodium hydroxide is used to adjust the pH value of the solution to 7.

[0121] Comparative Example 6

[0122] The solution and the printed circuit board in the present comparative example are prepared by substantially the same method as in Example 10, except that:

[0123] Sulfuric acid is used to adjust the pH value of the solution to 11.

[0124] Comparative Example 7

[0125] The solution and the printed circuit board in the present comparative example are prepared by substantially the same method as in Example 10, except that:

[0126] In step (1), the temperature of the pre-dissolution treatment is 25°C.

[0127] The parameters of the above examples and comparative examples are shown in Table 1 below.

[0128] Table 1

[0129]

[0130] In the table, " / " indicates that the substance is not present.

[0131] Performance Test

[0132] Test board A: 11.5 cm x 12 cm printed circuit board substrate.

[0133] Test board B: 5 cm x 10 cm double-sided fully covered ink FR4 copper clad board.

[0134] Test board C: printed circuit board substrate with poor ink curing.

[0135] The test board is a printed circuit board substrate to be treated. After the complete surface treatment process provided in the preparation method of the printed circuit board in the above examples and comparative examples, a printed circuit board is obtained.

[0136] (1) Ink adhesion

[0137] The test board A is subjected to pre-leaching treatment and water washing treatment, and after being blown dry, a 3M adhesive tape is used for adhesion and tearing test. Whether the ink falls off is evaluated according to the IPC-TM-650 2.4.1 standard.

[0138] (2) Nickel bath / gold bath deposition rate reduction ratio

[0139] (a) Initial rate (v1) determination: In a newly prepared nickel bath / gold bath, the test board A is treated according to the preparation method of the printed circuit board in the above examples and comparative examples, and the coating thickness is measured using a FISCHER thickness gauge (X-RAY XDV-μ), and the initial deposition rate v1 (μ" / min) is calculated.

[0140] (b) Bath liquid accelerated aging: The test board B is subjected to pre-leaching treatment and water washing treatment, and is directly immersed in the above nickel bath / gold bath (20 pieces of single treatment, repeated 40 times) to simulate the cumulative treatment of 2m 2 Production pollution of ink area.

[0141] (c) Determination of rate after aging (v2): The aged bath liquid is adjusted in concentration, and the test board A is treated again according to the preparation method of the printed circuit board in the above examples and comparative examples, and the deposition rate v2 (μ" / min) after aging is measured and calculated.

[0142] (d) Deposition rate reduction ratio calculation: Deposition rate reduction ratio (%) = (v1-v2) / v1 x 100%.

[0143] (3) Appearance of gold surface

[0144] The test board C treated completely according to the preparation method of the printed circuit board in the above examples and comparative examples is visually inspected to evaluate whether the gold surface is normal.

[0145] The test results are shown in Table 2.

[0146] Table 2

[0147]

[0148] In the table, " / " represents not tested.

[0149] As shown in Table 2, it can be seen from Comparative Examples 1-10 and Comparative Examples 1-7 that the solution provided by some embodiments of the application selectively dissolves small molecules and low-polymerization-degree molecules in the solder resist ink in advance without damaging the integrity of the main structure of the solder resist ink, reduces the amount of the solder resist ink dissolved in the electroless plating bath during the subsequent electroless plating process, effectively protects the bath from contamination, slows down the decrease in the deposition rate of the electroless plating layer, reduces the color difference of the gold surface, and improves product yield.

[0150] As can be seen from Comparative Examples 1-10 and Comparative Examples 1-3, when any one of the first compound, the second compound, and the third compound is absent from the solution, the decrease ratio of the deposition rate sharply decreases, and the appearance of the gold surface is poor. It can be proved that the first compound, the second compound, and the third compound have a synergistic effect in the solution and cannot be absent.

[0151] As can be seen from Comparative Examples 1-10 and Comparative Example 4, when the concentration of the first compound is too low, even if the other components and process parameters are within the appropriate range, the solution cannot effectively dissolve small molecules and low-polymerization-degree molecules.

[0152] As can be seen from Comparative Examples 1-10 and Comparative Example 5, the first compound (such as ethylenediamine) is replaced by malonic acid, which is a binary carboxylic acid without nitrogen and does not have a nitrogen-containing functional group. The solution lacks substances that can form complexes, and cannot effectively dissolve small molecules and low-polymerization-degree molecules.

[0153] As can be seen from Comparative Examples 1-10 and Comparative Example 6, when the pH value of the solution is too high, the strong alkaline environment attacks the main structure of the solder resist ink, resulting in oil throwing.

[0154] As can be seen from Comparative Examples 1-10 and Comparative Example 7, when the temperature of the pre-dissolution treatment is too low, the efficiency of the pre-dissolution is extremely low, and the purpose of removing contaminants cannot be achieved.

[0155] The technical features of the above-described embodiments can be combined arbitrarily. To make the description concise, all possible combinations of the technical features in the above-described embodiments are not described, however, as long as the combinations of the technical features do not contradict each other, they should be considered as falling within the scope of the present disclosure.

[0156] The above-described embodiments are merely illustrative of several embodiments of the present application, which are described in more detail and in a specific manner, but should not be construed as limiting the scope of the patent of the present application. It should be noted that, for those of ordinary skill in the art, without departing from the technical concept of the present application, a number of modifications and improvements can be made, which all belong to the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. A solution, characterized in that, include: The first compound is selected from at least one of nitrogen-containing carboxylic acids and their salts and water-soluble amine compounds; The second compound is selected from at least one of hydroxycarboxylic acids and their salts; as well as The third compound is selected from hypophosphite.

2. The solution according to claim 1, characterized in that, The nitrogen-containing carboxylic acid is selected from at least one of ethylenediaminetetraacetic acid, hydroxyethylethylenediaminetriacetic acid, dihydroxyethylethylenediaminediaacetic acid, propylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, triethylenetetraaminehexaacetic acid, glycine, iminodiaacetic acid, hydroxyethyliminodiaacetic acid, hypozinotriacetic acid, and hypozinotripropionic acid.

3. The solution according to claim 1, characterized in that, The water-soluble amine compound is selected from at least one of monoethanolamine, diethanolamine, triethanolamine, ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, methylamine, and dimethylamine.

4. The solution according to claim 1, characterized in that, The hydroxycarboxylic acid is selected from at least one of glycolic acid, diethylene glycolic acid, glyceric acid, malonic acid, lactic acid, malic acid, citric acid, tartaric acid, gluconic acid, glucoheponic acid, α-hydroxyglutaric acid, β-hydroxyglutaric acid, and β-hydroxybutyric acid.

5. The solution according to claim 1, characterized in that, Hypophosphite is selected from at least one of sodium hypophosphite, potassium hypophosphite, and ammonium hypophosphite.

6. The solution according to any one of claims 1 to 5, characterized in that, At least one of the following conditions must be met: (1) The concentration of the first compound is 0.01 mol / L to 2 mol / L; (2) The concentration of the second compound is 0.01 mol / L to 2 mol / L; (3) The concentration of the third compound is 0.01 mol / L to 1 mol / L; (4) The pH value of the solution is 4~9; (5) The solvent of the solution includes water.

7. A method for manufacturing a printed circuit board, characterized in that, Includes the following steps: The solder resist ink on the surface of the printed circuit board substrate is pre-dissolved using the solution described in any one of claims 1 to 6. The surface of the printed circuit board substrate after pre-dissolution treatment is subjected to chemical plating.

8. The method for manufacturing a printed circuit board according to claim 7, characterized in that, The pre-dissolution treatment satisfies at least one of the following conditions: (1) The temperature of the pre-dissolution treatment is 30℃~90℃; (2) The pre-dissolution treatment time is 2 min to 60 min; (3) The pre-dissolution treatment includes soaking treatment.

9. A printed circuit board, characterized in that, It is prepared using the printed circuit board preparation method as described in claim 7 or 8.

10. An electronic device, characterized in that, Including the printed circuit board as described in claim 9.

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