Gold surface cleaning method used in PCB (Printed Circuit Board) process

By using plasma cleaning methods in PCB processing, oxygen, nitrogen and argon are used for segmented cleaning, the problem of gold surface watermark after gold deposits is solved, material loss is reduced, and damage to green oil is avoided.

CN120076194APending Publication Date: 2025-05-30JIUJIANG SUNSHINE GLOBAL CIRCUITS TECHNOLOGY CO LTD
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Patent Information

Application Number
CN202510036884.4
Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Filing Date
2025-01-09
Publication Date
2025-05-30

AI Technical Summary

Technical Problem

During PCB processing, there is often a potion mark on the surface after the gold sinks, which affects the appearance and leads to scrapping. Conventional cleaning methods can easily damage the green oil, resulting in high material loss.

Method used

The plasma cleaning method is adopted, and the reaction time is 10-12 minutes by using oxygen, nitrogen and argon in the plasma machine to clean the reaction time is 10-12 minutes to avoid the participation of carbon tetrafluoride, so as to weaken the effect of plasma cleaning, and remove polar residues on the gold surface in a similar way to combustion.

Benefits of technology

It effectively avoids the appearance of golden-faced potion marks, reduces material losses, and simplifies the process flow, avoiding damage to green oil.

✦ Generated by Eureka AI based on patent content.

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Abstract

The invention discloses a gold surface cleaning method for a PCB (Printed Circuit Board) process, which comprises the following steps of: fixing a board body: enabling the board body with gold surface developing liquid medicine residues to penetrate through a non-electroplating hole of the board body through a fixing piece, and fixing the board body on an inner frame of a plasma machine; the plate bodies are cleaned in a segmented mode, the plate bodies are sequentially subjected to a reaction under the conditions of oxygen, nitrogen and argon through a plasma machine, and the reaction time is 10-12 min; inspecting, namely taking out the plate body subjected to the plasma reaction and inspecting; and gold immersion pretreatment: the baked plate body is subjected to gold immersion pretreatment, and the plate body without liquid medicine residues is obtained. The method solves the problems that in the prior art, after PCB gold immersion, the gold surface is scrapped due to chemical printing, and green oil damage is caused by conventional gold surface cleaning.
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Description

Technical Field

[0001] The present invention relates to the field of PCB processes, and particularly to a method for cleaning the gold surface in PCB processes. Background Art

[0002] In the prior art, during PCB processing, due to the residual developer solution on the copper surface during green oil development, there will be developer solution marks on the gold surface after immersion gold plating, which affects the appearance and directly leads to scrapping, resulting in extremely high material losses. There are also various reasons for this problem. For example, improper operation causes pollutants to adhere to the gold surface; half-plugged holes, small-scale oxidation near the vias; this type of oxidation is due to the unwashed developer solution in the vias or half-plugged holes or residual water vapor in the holes, and the developer solution slowly diffuses along the hole wall to the gold surface during the finished product storage stage to form dark brown oxides; poor water quality causes impurities in the water body to adsorb on the gold surface; the compactness of the gold surface is poor, and the nickel surface will have slight corrosion.

[0003] In view of this, the present technical solution proposes a method for cleaning the gold surface in PCB processes. Through plasma cleaning, without damaging the green oil, it avoids the problem of the gold surface appearance caused by the developer solution marks (organic) on the gold surface and directly leads to scrapping, reducing material losses. Summary of the Invention

[0004] The technical solution of the present invention aims to solve at least one of the technical problems in the related art to some extent. For this reason, the main purpose of the present invention is to provide a method for cleaning the gold surface in PCB processes, aiming to solve the problems that there will be developer solution marks on the gold surface after PCB immersion gold plating in the prior art, resulting in scrapping, and conventional gold surface cleaning will cause damage to the green oil.

[0005] To achieve the above purpose, the present invention provides a method for cleaning the gold surface in PCB processes, including fixing the board body. The board body with residual gold surface developer solution is fixed on the inner frame of the plasma machine after passing through the non-electroplated holes of the board body by a fixing member; segmented cleaning, the board body is reacted in the plasma machine in the order of oxygen, nitrogen, and argon conditions, and the reaction time is 10 - 12 minutes; inspection, the board body after plasma reaction is taken out for inspection; pre-treatment before immersion gold plating, the board body after baking is subjected to pre-immersion gold plating processes to obtain a board body without residual developer solution.

[0006] As a further solution of the present invention, in the step of fixing the board body, the fixing member is a steel hook structure.

[0007] As a further solution of the present invention, in the step of segmented cleaning, the reaction time is 11 minutes.

[0008] As a further solution of the present invention, in the step of pre-treatment before immersion gold plating, the pre-immersion gold plating processes include degreasing, micro-etching, and post-dipping.

[0009] As a further solution of the present invention, in the step of segmented cleaning, carbon tetrafluoride is not involved in the reaction.

[0010] As a further solution of the present invention, in the step of fixing the plate body, after the fixing member passes through the plate body, the plate body is in a non-shakeable state inside the ion machine.

[0011] As a further solution of the present invention, in the inspection step, the inspection method is visual inspection through a magnifying glass.

[0012] As a further solution of the present invention, in the step of segmented cleaning, the maximum vacuum temperature inside the ion machine is 90 °C.

[0013] As a further solution of the present invention, in the step of segmented cleaning, the pressure value in the vacuum chamber inside the ion machine is 200 - 230 pv.

[0014] The beneficial effects of the present invention are as follows:

[0015] The gold surface cleaning method for PCB process proposed by the present invention, by not involving carbon tetrafluoride in the reaction and only using oxygen, nitrogen and argon for the reaction, weakens the effect of plasma cleaning, and forms a method similar to combustion in a closed space under the atmosphere of oxygen and nitrogen to remove the polar residues on the gold surface, effectively avoiding the waste of materials. The overall implementation process is simple and easy to implement. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the technical solutions of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the technical solutions of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on the structures shown in these drawings.

[0017] Figure 1 It is a schematic block diagram of the main implementation steps of the present invention.

[0018] Figure 2 It is a physical diagram of the plate body with potion residues and the openings on the plate body in the present invention.

[0019] Figure 3 It is an enlarged physical view of the plate body taken out after plasma reaction in the present invention.

[0020] Figure 4 It is an enlarged physical view of the plate body after the pretreatment of immersion gold in the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0021] As follows:

[0022] Please refer to the attached Figures 1-4 ,

[0023] The main implementation steps include: fixing the board body. After passing the fixing part through the non-electroplating holes of the board body with the residual gold surface developing potion, fix it on the inner frame of the plasma machine; segmented cleaning. React the board body sequentially under the conditions of oxygen, nitrogen and argon through the plasma machine, and the reaction time is 10 - 12 minutes; inspection. Take out the board body after the plasma reaction and conduct inspection; pre-treatment before immersion gold. Conduct the pre-immersion gold process on the baked board body to obtain a board body without residual potion.

[0024] Process principle:

[0025] This process plan mainly uses oxygen, nitrogen and argon to remove glue from the PCB board, without using tetrafluoromethane as the plasma source, which weakens the effect of plasma cleaning. It forms a method similar to combustion in a closed space under the atmosphere of oxygen and nitrogen to remove polar residues on the gold surface, and has relatively little impact on the solder mask surface. If tetrafluoromethane is added (even in a small proportion), it will cause tetrafluoromethane to be decomposed into plasma under high voltage, attacking the gold surface and solder mask without difference, thus causing etching of the solder mask surface at high temperature and bringing new hidden dangers in the gold surface treatment while causing color difference in the solder mask.

[0026] A preferred embodiment of the present invention: In the step of fixing the board body, the fixing part is a steel hook structure.

[0027] A preferred embodiment of the present invention: In the step of segmented cleaning, the reaction time is 11 minutes.

[0028] A preferred embodiment of the present invention: In the pre-treatment step before immersion gold, the pre-immersion gold process includes degreasing, micro-etching and post-dipping.

[0029] A preferred embodiment of the present invention: In the step of segmented cleaning, tetrafluoromethane is not included in the reaction.

[0030] A preferred embodiment of the present invention: In the step of fixing the board body, after passing the fixing part through the board body, the board body is in an immovable state inside the ion machine.

[0031] A preferred embodiment of the present invention: In the inspection step, the inspection method is visual inspection through a magnifying glass.

[0032] A preferred embodiment of the present invention: In the step of segmented cleaning, the maximum vacuum temperature inside the ion machine is 90 °C.

[0033] A preferred embodiment of the present invention: In the step of segmented cleaning, the pressure value in the vacuum chamber inside the ion machine is 200 - 230 pv.

[0034] The above are only the preferred embodiments of the technical solution of the present invention, and do not limit the patent scope of the technical solution of the present invention. Any equivalent structural transformation made under the inventive concept of the technical solution of the present invention by using the content of the specification and drawings of the technical solution of the present invention, or directly / indirectly applied to other related technical fields, is included in the patent protection scope of the technical solution of the present invention.

Claims

1. A method for cleaning a gold surface in a PCB process, characterized in that: The steps include: S1, plate fixing, The plate with gold surface developer solution residue is fixed on the inner frame of the plasma machine after the fixing piece passes through the non-electroplating hole of the plate; S2, segment cleaning, The plate is reacted in oxygen, nitrogen and argon in sequence by a plasma machine, and the reaction time is 10-12 minutes; S3, inspection, Take out the plate after the plasma reaction and inspect it; S4, Pre-treatment of Immersion Gold, The baked board is processed before the gold precipitation process to obtain a board without chemical residue.

2. The method for cleaning the gold surface in the PCB process according to claim 1, characterized in that: In the plate fixing step, the fixing piece is a steel hook structure.

3. The gold surface cleaning method for PCB process according to claim 1, characterized in that: In the step of performing the stepwise washing, the reaction time was 11 min.

4. The gold surface cleaning method for PCB process according to claim 1, characterized in that: In the pre-immersion gold treatment steps, the pre-immersion gold process includes degreasing, micro-etching and post-immersion.

5. The method for cleaning the gold surface in PCB process according to claim 1, characterized in that: In the staged cleaning step, carbon tetrafluoride is not involved in the reaction.

6. The method for cleaning the gold surface in PCB process according to claim 1, characterized in that: In the plate fixing step, after the fixing piece passes through the plate, the plate is in a non-shakable state inside the ion generator.

7. The gold surface cleaning method for PCB process according to claim 1, characterized in that: In the inspection step, the inspection is performed by visual inspection through a magnifying glass.

8. The method for cleaning the gold surface in PCB process according to claim 1, characterized in that: During the staged cleaning step, the vacuum temperature inside the ionizer is up to 90 °C.

9. The method for cleaning the gold surface in PCB process according to claim 1, characterized in that: During the segmented cleaning step, the pressure value of the vacuum chamber inside the ionizer is 200-230pv.