A production process method of a PCB board

Abstract

The present application relates to the technical field of circuit board manufacturing, and particularly relates to a PCB production process method, which comprises an etching method for forming a circuit pattern, and the etching method is electrolytic etching. The PCB production process method provided by the present application replaces chemical etching in the traditional PCB production process with electrolytic etching, is green, environment-friendly and pollution-free, greatly saves production cost, improves workshop operation environment, and meets the strict acceptance standards of clean and civilized production.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of circuit board manufacturing, and particularly relates to a production process method of a PCB board. BACKGROUND

[0002] The PCB board, i.e. a printed circuit board, is generally a copper-clad substrate, and is a carrier for realizing the mutual connection between electronic components. The single-sided PCB board is the most basic PCB board, and parts are concentrated on one side, and wires are concentrated on the other side of the board. There are many types of single-sided PCB boards on the market, which are suitable for various industries and fields, such as computers, digital products, medical devices, aerospace, etc.

[0003] The manufacturing process of the conventional single-sided PCB board includes the following steps: performing a line printing pre-treatment on the single-sided board, directly printing a line pattern on one side with line ink, for a single-sided PCB board with a relatively complex line pattern and high precision requirements, performing an exposure and development process after pre-baking, performing text printing on the other side after the line ink printing on the one side is completed, forming a line pattern through chemical etching after baking, removing the line ink shielding the line pattern, performing a whole surface anti-soldering treatment on the line surface with anti-soldering ink, directly exposing the PAD (soldering pad) part through the record of engineering data, and finally completing the subsequent surface treatment processes required by the customer.

[0004] In the manufacturing process of the conventional single-sided PCB board, about 6000 kg of acid etching liquid is consumed per month (based on 50% of the residual copper area of the board and 0.6 kg of etching liquid per square meter), and the cost of the etching liquid is about 20,000 yuan per square meter (based on 2 yuan per square meter), the amount of water consumed is about 300,000-500,000 tons, and the cost of waste water treatment is at least 500,000 yuan. In addition to the labor cost, the comprehensive conversion cost is about 25-40 yuan / m2, and the production cost is high. 2 Moreover, the chemical etching method used in the manufacturing process of the single-sided PCB board produces copper-containing etching waste liquid, and the step of removing the line-shielding ink produces ink-removing waste liquid. The copper-containing etching waste liquid and the ink-removing waste liquid seriously pollute the natural environment, and the copper-containing etching waste liquid is a HW22 type hazardous waste in the national hazardous waste list. Moreover, the copper-containing etching waste liquid needs to be transported away for treatment by a business with environmental protection qualification using a special hazardous goods transport vehicle. This not only greatly increases the cost of producing the single-sided PCB board, but also significantly increases the risks in the hazardous goods transport process. SUMMARY

[0005] The present application relates to the technical field of circuit board manufacturing, and particularly relates to a production process method of a PCB board.

[0006] Therefore, the present application aims to solve the technical problem of overcoming the defects of the prior art, i.e. the copper-containing etching waste liquid produced in the PCB production process pollutes the environment and the production cost is high, thereby providing an environmentally friendly, economical and streamlined PCB production process.

[0007] To solve the above technical problems, the technical solution adopted by the present application is as follows:

[0008] A PCB production process method, comprising an etching method for forming a circuit pattern, wherein the etching method is electrolytic etching.

[0009] Further, the pH value of the electrolyte used in the electrolytic etching is 3-5.

[0010] Further, the composition of the electrolyte mainly includes sulfuric acid, copper sulfate, chloride ions and pure water, the concentration of sulfuric acid in the electrolyte is 180-250 g / L, the concentration of copper sulfate is 60-90 g / L, and the concentration of chloride ions is 60-80 ppm.

[0011] Further, the electrolytic etching is carried out at a constant voltage of 1.0-15.0 V.

[0012] Further, before the electrolytic etching method, resist ink is used for printing the circuit pattern.

[0013] Further, the resist ink is a solder mask ink.

[0014] Further, the PCB production process method further comprises the steps of directly performing laser opening of a sky window after the electrolytic etching method is completed; or, after the electrolytic etching method is completed, first performing the step of printing the solder mask ink again, and then performing the step of laser opening of the sky window after the step of printing the solder mask ink is completed again.

[0015] Further, the PCB production process method specifically comprises the following steps:

[0016] S1, a single-sided board is subjected to a printing pretreatment;

[0017] S2, the side of the single-sided board with copper foil is printed with a circuit pattern using solder mask ink;

[0018] S3, the other side of the single-sided board is printed with text;

[0019] S4, electrolytic etching is performed to form a circuit pattern;

[0020] S5, laser opening of a solder mask sky window is performed to expose the PAD part that needs to be connected or installed with a connector.

[0021] Further, when the thickness of the resist ink in the S2 step is 6-8 μm, a step of printing a secondary anti-welding ink to a preset thickness, which is the total anti-welding layer thickness required by the customer, is further included between the steps of S4 and S5.

[0022] The technical scheme of the present application has the following beneficial effects:

[0023] 1. The production process of the PCB provided by the present application replaces the chemical etching in the traditional PCB production process with electrolytic etching. Since the present application does not use the chemical etching method, a large amount of various chemical solutions and a large amount of cleaning water are saved, and no copper-containing etching waste liquid is generated, so there is no need to spend cost to treat the copper-containing etching waste liquid, which greatly saves the production cost and meets the green and environmentally friendly production requirements, and there is no risk of transporting hazardous waste. At the same time, the electrolyte used in the electrolytic etching method has no pollution, and the electrolyte can be repeatedly used for a long time. Only when the concentration of the electrolyte is lowered after being used for a period of time, the raw materials need to be appropriately added for continuous use, further reducing the production cost. During electrolytic etching, the copper on the circuit board that is not covered by the ink and exposed to the outside is directly deposited and attached to the cathode plate under the action of an external electric field, thereby obtaining electrolytic copper with a purity higher than 95%. The electrolytic copper can be directly used or sold, so the method of the present application can also increase the by-products, thereby obtaining by-product income. In summary, the PCB production process provided by the present application has the advantages of being green and environmentally friendly, greatly saving the production cost, directly increasing the by-product income, greatly improving the working environment of the workshop, and meeting the acceptance standards of clean and civilized production.

[0024] 2. The production process of the PCB provided by the present application limits the pH value of the electrolyte and the concentrations of sulfuric acid, copper sulfate and chloride ions in the electrolyte to prevent defects such as poor etching factor and large side etching amount, thereby better ensuring the yield of the circuit.

[0025] 3. The production process of the PCB provided by the present application uses ordinary circuit ink in combination with the electrolytic etching process to obtain a product with a yield of about 90%; further, when the anti-welding ink is used instead of the ordinary circuit ink in the prior art to print the circuit pattern, the anti-welding ink has better etching resistance, which can further ensure the etching effect and can increase the production yield to about 99%, thereby significantly improving the yield of the produced PCB.

[0026] 4.The PCB production process provided by the application, the inventor found in production practice that although the solder mask ink has a better etching resistance, the solder mask ink is difficult to remove, therefore, the inventor exposes the PAD part requiring connection or installation of a connector by directly using the laser to open a sky window after forming a circuit pattern by electrolytic etching instead of removing the ink, the use of the solder mask ink in combination with the laser to open a sky window can effectively omit the step of removing the ink, and further, the stripping solution is not needed, so there is no stripping waste liquid to be discharged, and a large amount of clean water is not needed to clean the single-sided PCB after the stripping solution treatment, therefore, the process flow is shortened, the production efficiency is improved, the production cost is greatly saved, and the discharge and treatment of the ink-containing waste liquid are further eliminated.

[0027] In addition, the precision of the laser to open a solder mask sky window is much higher than the method of exposing the PAD part requiring connection or installation of a connector by developing a printed film after printing a resist, so that the accuracy of the circuit pattern production of the PCB is further improved.

[0028] 6.The PCB production process provided by the application, for a circuit pattern board with a higher voltage requirement, a second printing of solder mask ink is performed after the electrolytic etching of the circuit pattern, and then the laser is used to open a solder mask sky window, the above method further improves the insulation, moisture resistance, corrosion resistance and high temperature resistance of the PCB, and more effectively improves the service life of the circuit board. DETAILED DESCRIPTION

[0029] The following examples are provided to better further understand the application, and are not limited to the best mode, and do not constitute a limitation on the content and protection scope of the application, any person under the inspiration of the application or the combination of the application with other prior art features obtains any product same or similar to the application, which falls within the protection scope of the application.

[0030] The specific experimental steps or conditions are not indicated in the examples, and can be performed according to the conventional experimental steps described in the literature in the art. The reagents or instruments used are not indicated by the manufacturer, and are conventional reagent products that can be obtained by purchase.

[0031] The single-sided board is a single-sided copper-clad substrate with a copper foil thickness of 35μm, and the substrate material is FR-1, which is purchased from the Jiangsu Guantao Group Co., Ltd.;

[0032] The circuit ink is LH-7100, which is purchased from the Jiangsu Guangxin Photosensitive New Material Co., Ltd.;

[0033] The anti-soldering ink is an anti-soldering green ink, and its brand is KSM-28, which is purchased from Jiangsu Guangxin Photographic New Material Co., Ltd.

[0034] Embodiment 1

[0035] The embodiment provides a PCB production process, which specifically comprises the following steps:

[0036] S1, before printing, the single-sided board is subjected to surface pickling by using dilute sulfuric acid with a mass concentration of 5%, and then is washed with clean water, and then is subjected to grinding and brushing treatment by using a nylon brush with a mesh of 600, and is dried at 90 DEG C after washing;

[0037] S2, one side of the single-sided board with copper foil is printed with an anti-soldering ink to form a circuit pattern: the Guangxin green ink is used to print the circuit pattern on the surface of the single-sided board after the pretreatment, and the ink thickness of the circuit pattern is 15 μm, and then the single-sided board after the printing of the circuit pattern is baked at 150 DEG C for 30 min;

[0038] S3, the other side of the single-sided board, i.e. the substrate side, is printed with characters: white character ink is used to print characters on the other side of the single-sided board after the printing of the circuit pattern, and then the single-sided board after the printing of the characters is baked at 130 DEG C for 20 min;

[0039] S4, electrolytic etching is performed to form a circuit pattern: the single-sided board after the treatment in the step S3 is loaded on an electrolytic line, and is conveyed to an electrolyte at 35 DEG C by using a conductive clamp, and then is subjected to electrolysis at a constant voltage of 5.0 V for 15 min; the electrolyte mainly comprises sulfuric acid, copper sulfate, chloride ions and pure water, the concentration of the sulfuric acid in the electrolyte is 220 g / L, the concentration of the copper sulfate is 60 g / L, the concentration of the chloride ions is 70 ppm, and the pH value of the electrolyte is 3.0;

[0040] S5, laser opening of the anti-soldering window: a laser machine is used to open a window on the single-sided board after the electrolytic etching, so that the PAD part which needs to be connected or mounted with a connector is exposed to obtain a PCB board; the laser head used in the opening of the window has a diameter of 18 μm, the mirror scanning area is 45*45 mm, and the scanning ablation frequency is set to 1000 KHZ.

[0041] The yield of the PCB board prepared by the method of the embodiment is 99.8%.

[0042] Embodiment 2

[0043] The embodiment provides a PCB production process, which is different from the embodiment 1 only in that the concentration of the sulfuric acid in the electrolyte used in the step S4 is 180 g / L, the concentration of the copper sulfate is 70 g / L, the concentration of the chloride ions is 80 ppm, and the pH value of the electrolyte is 5.0.

[0044] The yield of the PCB prepared by the method of the embodiment is 99.5%.

[0045] Embodiment 3

[0046] The embodiment provides a production process method of a PCB, and the only difference from the embodiment 1 is that the concentration of sulfuric acid in the electrolyte used in the step S4 is 180 g / L, the concentration of copper sulfate is 70 g / L, the concentration of chloride ions is 60 ppm, and the pH value of the electrolyte is 4.0.

[0047] The yield of the PCB prepared by the method of the embodiment is 99.6%.

[0048] Embodiment 4

[0049] The embodiment provides a production process method of a PCB, and the only difference from the embodiment 1 is that the step S4 is electrolytic etching at a constant voltage of 12.0 V.

[0050] The yield of the PCB prepared by the method of the embodiment is 96.5%.

[0051] Embodiment 5

[0052] The embodiment provides a production process method of a PCB, and the only difference from the embodiment 1 is that the step S4 is electrolytic etching at a constant voltage of 1.0 V.

[0053] The yield of the PCB prepared by the method of the embodiment is 98.7%.

[0054] Embodiment 6

[0055] The embodiment provides a production process method of a PCB, and the only difference from the embodiment 1 is that the step S2 is baking at a temperature of 100 DEG C for 20 min after printing the circuit pattern.

[0056] The yield of the PCB prepared by the method of the embodiment is 91.6%.

[0057] Embodiment 7

[0058] The embodiment provides a production process method of a PCB, and the only difference from the embodiment 1 is that the step S2 is baking at a temperature of 150 DEG C for 10 min after printing the circuit pattern.

[0059] The yield of the PCB prepared by the method of the embodiment is 96.8%.

[0060] Embodiment 8

[0061] The embodiment provides a PCB production process method, and the only difference from the embodiment 1 is that the ink used in the step S2 is a circuit ink with a brand XZ-3000, which is purchased from the Changda Electronic Science and Technology Material Co., Ltd.

[0062] The good product rate of the PCB prepared by the method of the embodiment is 89.0%.

[0063] Embodiment 9

[0064] The embodiment provides a PCB production process method, and the only difference from the embodiment 1 is that the ink used in the step S2 is a circuit ink with a brand XZ-3000, which is purchased from the Changda Electronic Science and Technology Material Co., Ltd.

[0065] S1, performing printing pretreatment on the single-sided board: using dilute sulfuric acid with a mass concentration of 5% to perform surface pickling on the single-sided board after finishing layout and cutting, then washing with clean water, then performing grinding and brushing treatment by using a nylon brush with a mesh of 600, and drying at 90 ℃ after washing;

[0066] S2, printing circuit patterns on one side of the single-sided board with copper foil by using anti-soldering ink: printing circuit patterns on the surface of the single-sided board after the pretreatment by using Guangxin green oil, the ink thickness of the circuit patterns is 6 μm, then baking the single-sided board after printing the circuit patterns at 150 ℃ for 30 min;

[0067] S3, printing characters on the other side of the single-sided board, that is, the substrate side: printing characters on the other side of the single-sided board after printing the circuit patterns by using white character ink, then baking the single-sided board after printing the characters at 130 ℃ for 20 min;

[0068] S4, forming circuit patterns by electrolytic etching: loading the single-sided board after the step S3 into an electrolytic line, conveying to an electrolyte at 35 ℃ by using a conductive clamp, then electrolyzing at a constant voltage of 5.0 V for 15 min; the electrolyte is mainly composed of sulfuric acid, copper sulfate, chloride ions and pure water, the concentration of the sulfuric acid in the electrolyte is 220 g / L, the concentration of the copper sulfate is 60 g / L, the concentration of the chloride ions is 70 ppm, and the pH value of the electrolyte is 3.0;

[0069] S5, printing anti-soldering ink again: printing anti-soldering ink on the single-sided board with circuit patterns obtained in the step S4, the printing thickness is 9 μm, then baking the single-sided board after printing the circuit patterns at 150 ℃ for 30 min;

[0070] S6, opening anti-soldering skylights by using a laser machine: opening skylights on the single-sided board after the second printing by using a laser machine, so that the PAD parts needing to be connected or mounted with connectors are exposed to obtain a PCB, the diameter of the laser head used when opening the skylights is 18 μm, the scanning area of the galvanometer is 45*45 mm, and the scanning ablation frequency is set to 1000 KHZ.

[0071] The yield of the PCB prepared by the method of the embodiment is 99.9%.

[0072] Embodiment 10

[0073] The embodiment provides a production process method of a PCB, and specifically comprises the following steps:

[0074] S1, performing printing pretreatment on the single-sided board: using dilute sulfuric acid with a mass concentration of 3% to perform surface pickling on the single-sided board after finishing layout and cutting, then washing with clean water, and then performing grinding and brushing treatment by using a nylon brush with a mesh of 900, and drying at 80 DEG C after washing;

[0075] S2, printing circuit pattern on one side of the single-sided board with copper foil by using anti-soldering ink: printing the circuit pattern on the surface of the single-sided board after the pretreatment by using Guangxin green oil, the ink thickness of the circuit pattern is 15 μm, then baking the single-sided board after printing the circuit pattern at 150 DEG C for 30 min;

[0076] S3, printing characters on the other side of the single-sided board, i.e. the substrate side: printing characters on the other side of the single-sided board after printing the circuit pattern by using white character ink, then baking the single-sided board after printing the characters at 130 DEG C for 20 min;

[0077] S4, forming the circuit pattern by electrolytic etching: loading the single-sided board after the treatment in the S3 step on an electrolytic line, conveying to the electrolyte at 30 DEG C by using a conductive clamp, then electrolyzing at a constant voltage of 5.0 V for 15 min; the electrolyte mainly comprises sulfuric acid, copper sulfate, chloride ion and pure water, the concentration of the sulfuric acid in the electrolyte is 220 g / L, the concentration of the copper sulfate is 60 g / L, the concentration of the chloride ion is 70 ppm, and the pH value of the electrolyte is 3.0;

[0078] S5, opening the anti-soldering skylight by using a laser: opening the skylight on the single-sided board after etching by using a laser machine, so that the PAD part needing to be connected or mounted with a connector is exposed to obtain the PCB, the diameter of the laser head used in the opening of the skylight is 18 μm, the mirror scanning area is 45*45 mm, and the scanning ablation frequency is set to 1000 KHZ.

[0079] The yield of the PCB prepared by the method of the embodiment is 97.8%.

[0080] Embodiment 11

[0081] The embodiment provides a production process method of a PCB, and specifically comprises the following steps:

[0082] S1, performing printing pretreatment on the single-sided board: using dilute sulfuric acid with a mass concentration of 5% to perform surface pickling on the single-sided board after finishing layout and cutting, then washing with clean water, and then performing grinding and brushing treatment by using a nylon brush with a mesh of 600, and drying at 70 DEG C after washing;

[0083] S2, printing circuit pattern on one side of single panel with copper foil using solder mask ink: printing circuit pattern on the surface of single panel after pretreatment using Guangxin green ink, the ink thickness of circuit pattern is 15 μm, then baking the single panel with printed circuit pattern at 150°C for 30 min;

[0084] S3, printing text on the other side of single panel, i.e. substrate side: printing text on the other side of single panel with printed circuit pattern using white text ink, then baking the single panel with printed text at 130°C for 20 min;

[0085] S4, forming circuit pattern by electrolytic etching: loading the single panel treated in S3 step on electrolytic line, conveying to electrolyte at 32°C by conductive clamp, then electrolyzing at 5.0 V for 15 min; the electrolyte mainly consists of sulfuric acid, copper sulfate, chloride ion and pure water, the concentration of sulfuric acid in electrolyte is 220 g / L, the concentration of copper sulfate is 60 g / L, the concentration of chloride ion is 70 ppm, and the pH value of electrolyte is 3.0;

[0086] S5, opening solder mask skylight by laser: opening skylight on the single panel after electrolytic etching by laser machine, so that the PAD part needing to be connected or installed with connector is exposed to obtain PCB board, the diameter of laser head used in opening skylight is 18 μm, the mirror scanning area is 45 x 45 mm, and the scanning ablation frequency is set to 1000 KHZ.

[0087] The yield of PCB board prepared by the method of the present embodiment is 98.1%.

[0088] Example 12

[0089] The present embodiment provides a production process method of PCB board, the only difference from Example 1 is that the electrolytic etching in S4 step is performed at a constant voltage of 15.0 V.

[0090] The yield of PCB board prepared by the method of the present embodiment is 92.3%.

[0091] Example 13

[0092] The present embodiment provides a production process method of PCB board, the only difference from Example 1 is that the concentration of sulfuric acid in the electrolyte in S4 step is 250 g / L, the concentration of copper sulfate is 90 g / L, and the concentration of chloride ion is 70 ppm.

[0093] The yield of PCB board prepared by the method of the present embodiment is 95.0%.

[0094] Test Example 1

[0095] The PCBs obtained in Examples 1-13 were subjected to AOI testing, and the quality test results are shown in Table 1.

[0096] Table 1. Test result summary table of example test boards

[0097]

[0098]

[0099] The production process of the PCB provided by the application can repeatedly use the electrolyte for a long time. The electrolyte can be continuously used after adding raw materials to supplement the electrolyte after the concentration of the electrolyte is lowered after being used for a period of time. A large amount of copper-containing etching waste liquid is not generated, so there is no need to spend cost to treat the copper-containing etching waste liquid. There is no consumption of developing liquid and stripping liquid, and there is no discharge of stripping wastewater. In addition, the copper in the area of 50% residual copper can be directly electrolyzed and reused. If the cost of the solder resist ink is calculated as 30 yuan / kg, and the monthly production capacity is 10,000 square meters, and the labor cost is not calculated, the conversion cost of the application is only 15-30 yuan / m 2 The production cost is greatly saved, the process flow is shortened, and the working environment of the workshop is greatly improved.

[0100] The above examples are merely examples for clarity and do not limit the embodiments. Based on the above description, other different forms of changes or variations can be made by those of ordinary skill in the art, and all embodiments do not need to be exhausted, and obvious changes or variations still fall within the protection scope of the application.

Claims

1. A process for the production of PCB boards, comprising an etching method for forming a circuit pattern, characterized in that, The etching method is electrolytic etching; The pH value of the electrolyte used in the electrolytic etching is 3-5, and the components of the electrolyte mainly include sulfuric acid, copper sulfate, chloride ion and pure water, the concentration of sulfuric acid in the electrolyte is 180-250 g / L, the concentration of copper sulfate is 60-90 g / L, and the concentration of chloride ion is 60-80 ppm; The electrolytic etching is carried out at a constant voltage of 1.0-15.0 V; Before the electrolytic etching method, the printing of the circuit pattern is carried out by using the resist ink, and the resist ink is the anti-welding ink.

2. The method of claim 1, wherein the PCB is a multilayer PCB. It also includes the step of directly carrying out laser opening of the sky window after the electrolytic etching method is completed; or, after the electrolytic etching method is completed, the step of again printing the anti-welding ink is carried out first, and then the step of laser opening of the sky window is carried out after the anti-welding ink is printed again.

3. The PCB production process of claim 1 or 2, wherein, Specifically, the steps include: S1, the single-sided panel is subjected to printing pretreatment; S2, the single-sided panel is subjected to printing of the circuit pattern by using the anti-welding ink on one side of the copper foil; S3, the other side of the single-sided panel is subjected to printing of characters; S4, the electrolytic etching is carried out to form the circuit pattern; S5, the laser opening of the anti-welding sky window is carried out to expose the PAD part which needs to be connected or mounted with the connector.

4. The method of claim 3, wherein the PCB is produced by a process comprising: When the thickness of the resist ink in the S2 step is 6-8 μm, the step of twice printing of the anti-welding ink to a preset thickness is further included between the steps of S4 and S5.

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