Copper plating process method for PCB (Printed Circuit Board) circuit copper foil

Abstract

The invention relates to a PCB (Printed Circuit Board) circuit copper thin copper plating process method, which comprises the following steps of: grinding a board, namely grinding off printing ink on a PCB circuit pattern to expose the circuit pattern and keep the printing ink at a non-circuit pattern position; electroplating copper: adding a layer of metal copper at the exposed circuit on the PCB through electrolytic reaction so as to enable the copper thickness of the circuit to meet the requirement; resistance welding: carrying out screen printing on a layer of photosensitive ink on the circuit pattern of the PCB by using a screen printing plate, then exposing by using a film to manufacture a resistance welding pattern, and finally developing; according to the method, printing ink on a circuit pattern of a PCB subjected to resistance welding can be ground off through a grinding board, at the moment, the circuit pattern is exposed, printing ink at the position of a non-circuit pattern is reserved, a layer of metal copper is added on the circuit pattern through electroplating copper treatment so that the copper thickness of the circuit pattern can meet the requirement, and finally resistance welding treatment is conducted. Therefore, the copper plating process of the PCB copper thin circuit is completed, and a series of adverse effects generated in the re-washing and ink removing process can be avoided.

Description

Technical Field

[0001] The invention relates to the technical field of PCBs, and in particular to a PCB circuit copper thin-film plating process method. Background Art

[0002] During the PCB production process, the copper of the circuits flowing into the later process may be thin due to some reasons (such as electroplating parameters, chemicals, tester abnormalities, etc.). In order to avoid affecting the overall quality of the PCB board, the circuits need to be electroplated with copper to increase the copper thickness of the circuits.

[0003] For PCB boards after the solder mask process, there is a layer of ink on the surface of the PCB board. The conventional rework process is: ink stripping - copper electroplating - solder mask process.

[0004] However, the ink removal and rework process consumes a large amount of ink and is difficult to clean out the ink in the plugged hole, resulting in poor plugging. The rewashing also increases the risk of ink entering the hole. Summary of the invention

[0005] In view of this, it is necessary to provide a PCB circuit copper thin copper plating process method to solve the problems in the conventional rework process, such as large ink consumption during ink removal and rework, difficulty in rewashing the ink in the plugging position, resulting in poor plugging, and rewashing will increase the risk of ink entering the hole.

[0006] The present invention provides a PCB circuit copper thin copper plating process method, which processes a PCB board that has been solder resisted and has a copper thin defect, comprising the following steps: Grinding the board to remove the ink on the circuit pattern of the PCB board, so that the circuit pattern is exposed and the ink on the non-circuit pattern is retained; Electroplating copper, adding a layer of metal copper to the exposed circuit pattern on the PCB board through electrolytic reaction, so that the copper thickness of the circuit pattern meets the requirements; Solder mask, a layer of photosensitive ink is screen-printed on the circuit pattern of the PCB board, and then exposed with film to make the solder mask pattern, and finally developed.

[0007] Furthermore, a ceramic grinding plate process is adopted, wherein the grinding plate current is 0.15A-0.25A.

[0008] Furthermore, the depth of the grinding plate is not less than the thickness of the ink on the circuit pattern before grinding, so as to clean the ink on the circuit pattern, and the grinding plate does not contact the ink on the non-circuit pattern of the PCB board.

[0009] Furthermore, the circuit pattern includes a circuit and a PAD.

[0010] Furthermore, the grinding plate comprises: Grind off the ink on the circuits and PADs of the PCB board to expose the circuits and PADs and retain the ink on non-circuits and non-PADs.

[0011] Further, the copper electroplating comprises: A layer of metal copper is added to the exposed circuits and PADs on the PCB through electrolytic reaction so that the copper thickness of the circuits and PADs meets the requirements.

[0012] Further, the solder resist comprises: A layer of photosensitive ink is screen-printed on the circuits and PADs of the PCB board, then exposed with film to make the solder mask pattern, and finally developed.

[0013] Furthermore, a blocking point screen printing oil process is adopted, wherein a screen is used with only the circuits and PADs covered with ink, and during the exposure process, a film is used to block the light irradiating to part of the PAD, the light-shielded ink is not solidified, the ink on the non-light-shielded circuits and part of the PAD is solidified, and the ink on the light-shielded part of the PAD is washed away by development to form a solder mask pattern.

[0014] Furthermore, the oil level of the screen cover is 1-2 mm larger than that of the PAD and the single side of the line.

[0015] Furthermore, the film exposure position is 0.05-0.10 mm larger than the PAD and the single side of the circuit.

[0016] Compared with the prior art, the ink on the circuit pattern of the PCB board that has completed the solder mask can be ground off by a grinding plate. At this time, the circuit pattern is exposed and the ink on the non-circuit pattern is retained. Through electroplating copper treatment, a layer of metal copper is added to the circuit pattern to make the copper thickness of the circuit pattern meet the requirements. Finally, solder mask treatment is performed, which completes the copper plating process of the PCB copper thin circuit, and can avoid a series of adverse effects caused by the backwashing and ink removal process. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A schematic diagram of a process flow in a PCB circuit copper thin plating process method provided by an embodiment of the present invention; Figure 2 A schematic diagram of a top view of a PCB board after implementing the PCB circuit copper thin-film plating process method provided by an embodiment of the present invention; Figure 3 for Figure 2 Sectional view of the middle AA plane; Figure 4 for Figure 3 The enlarged schematic diagram of the middle A part; Figure 5 for Figure 3 Enlarged schematic diagram of part B in the middle.

[0018] In the figure, 100-plate; 200-original ink; 300-circuit pattern, 310-circuit, 320-PAD; 400-photosensitive ink. DETAILED DESCRIPTION

[0019] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not used to limit the scope of the present invention.

[0020] like Figure 1 As shown, a PCB circuit copper thin copper plating process method provided by the present invention processes a PCB board that has been solder-resisted and has a copper thin defect, comprising the following steps: Step S100, grinding the board to remove the ink on the circuit pattern of the PCB board, so that the circuit pattern is exposed and the ink on the non-circuit pattern is retained; Step S200, electroplating copper, adding a layer of metal copper on the exposed circuit pattern on the PCB board through electrolytic reaction, so that the copper thickness of the circuit pattern meets the requirements; Step S300, solder mask, screen print a layer of photosensitive ink on the circuit pattern of the PCB board with a screen, then use film to expose to make solder mask pattern, and finally develop.

[0021] During implementation, the ink on the circuit pattern 300 of the PCB board that has completed the solder mask can be ground off by a grinding plate. At this time, the circuit pattern 300 is exposed and the ink on the non-circuit pattern is retained. Through electroplating copper treatment, a layer of metal copper is added to the circuit pattern 300 to make the copper thickness of the circuit pattern 300 meet the requirements. Finally, solder mask treatment is performed, which completes the copper plating process of the PCB copper thin circuit, and can avoid a series of adverse effects caused by the backwashing and ink removal process.

[0022] It should be noted that the circuit pattern 300 on the PCB board before grinding is a structure protruding from the pressed plate 100. When the copper thickness of the circuit pattern 300 is detected to be thin, the ink 200 on the circuit pattern needs to be ground, that is, the processing process recorded in step S100.

[0023] In step S100, a ceramic grinding plate process is adopted, wherein the grinding plate current is 0.15A-0.25A.

[0024] During the grinding process, the grinding depth is not less than the thickness of the ink on the circuit pattern 300 before grinding, so as to grind the ink on the circuit pattern 300 cleanly, and the grinding process does not contact the ink on the non-circuit pattern of the PCB. Through the above arrangement, it is possible to ensure that the original ink 200 on the circuit pattern 300 is grinded cleanly, and at the same time, avoid grinding the ink on the non-circuit pattern.

[0025] The circuit pattern 300 in this embodiment includes a circuit 310 and a PAD 320 (ie, a pad). It is understandable that the PAD 320 may be in a circular, square, or triangular shape, and the shape of the PAD 320 is not limited in this embodiment.

[0026] In step S100, grinding the plate includes: The ink on the circuit 310 and PAD 320 of the PCB board is ground off to expose the circuit 310 and PAD 320 and to retain the ink on the non-circuit 310 and non-PAD 320 .

[0027] In step S200, electroplating copper includes: A layer of metal copper is added to the exposed circuit 310 and PAD 320 on the PCB board through electrolytic reaction, so that the copper thickness of the circuit 310 and PAD 320 meets the requirements.

[0028] In step S300, solder resist includes: A layer of photosensitive ink 400 is screen-printed on the circuit 310 and PAD 320 of the PCB board, and then exposed with a film to produce a solder mask pattern, and finally developed.

[0029] It is understandable that if Figure 2-3 As shown, the PAD320 may be covered with oil or not, depending on actual needs. Figure 4 As shown, PAD320 is not covered with oil. Figure 5 As shown, the PAD 320 and the circuit 310 surrounding it are both coated with cured photosensitive ink 400 .

[0030] In one embodiment, a blocking point screen printing oil process is used, wherein a screen with ink only on the circuit 310 and PAD320 is used, and during the exposure process, a film is used to block the light irradiated to a part of PAD320, the light-shielded ink is not solidified, the ink on the non-light-shielded circuit 310 and part of PAD320 is solidified, and the ink on the light-shielded part of PAD320 is washed away by development to form a solder mask pattern.

[0031] Among them, the oil level of the screen cover is 1-2mm larger than the single side of PAD320 and circuit 310 to ensure that during the solder mask process, the screen-printed photosensitive ink 400 can completely cover the entire circuit 310 and PAD320. At the same time, the film exposure position is 0.05-0.10mm larger than the single side of PAD320 and circuit 310, and the error range is controlled within plus or minus 35um. Through the above settings, it can be ensured that the cured photosensitive ink 400 can accurately cover the entire circuit 310 and PAD320.

[0032] Compared with existing technologies: The ink on the circuit pattern 300 of the PCB board that has completed the solder mask can be ground off by a grinding plate. At this time, the circuit pattern 300 is exposed and the ink in the non-circuit pattern is retained. Through electroplating copper treatment, a layer of metal copper is added to the circuit pattern 300 to make the copper thickness of the circuit pattern 300 meet the requirements. Finally, solder mask treatment is performed, which completes the copper plating process of the PCB copper thin circuit and avoids a series of adverse effects caused by the backwashing and ink removal process.

[0033] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A PCB circuit copper thin copper plating process method, which processes a PCB board that has been soldered and has copper thin defects, characterized in that: The following steps are involved: Grinding the board to remove the ink on the circuit pattern of the PCB board, so that the circuit pattern is exposed and the ink on the non-circuit pattern is retained; Electroplating copper, adding a layer of metal copper to the exposed circuit pattern on the PCB board through electrolytic reaction, so that the copper thickness of the circuit pattern meets the requirements; Solder mask, a layer of photosensitive ink is screen-printed on the circuit pattern of the PCB board, and then exposed with film to make the solder mask pattern, and finally developed.

2. The PCB circuit copper thin-film plating process according to claim 1, characterized in that: A ceramic grinding plate process is adopted, wherein the grinding plate current is 0.15A-0.25A.

3. The PCB circuit copper thin-film plating process according to claim 1, characterized in that: The depth of the grinding plate is not less than the thickness of the ink on the circuit pattern before grinding, so as to clean the ink on the circuit pattern, and the grinding plate does not contact the ink on the non-circuit pattern of the PCB board.

4. The PCB circuit copper thin-film plating process according to claim 1, characterized in that: The circuit pattern includes a circuit and a PAD.

5. The PCB circuit copper thin-film plating process according to claim 4, characterized in that: The grinding plate comprises: Grind off the ink on the circuits and PADs of the PCB board to expose the circuits and PADs and retain the ink on non-circuits and non-PADs.

6. The PCB circuit copper thin-film plating process according to claim 4, characterized in that: The copper electroplating comprises: A layer of metal copper is added to the exposed circuits and PADs on the PCB through electrolytic reaction so that the copper thickness of the circuits and PADs meets the requirements.

7. The PCB circuit copper thin-film plating process according to claim 4, characterized in that: The solder resist comprises: A layer of photosensitive ink is screen-printed on the circuits and PADs of the PCB board, then exposed with film to make the solder mask pattern, and finally developed.

8. The PCB circuit copper thin-film plating process according to claim 7, characterized in that: A dot-blocking screen printing oil process is used, in which a screen with ink only on the circuits and PADs is used. During the exposure process, a film is used to block the light irradiating part of the PAD. The light-shielded ink is not solidified, and the ink on the non-light-shielded circuits and part of the PAD is solidified, and the ink on the light-shielded part of the PAD is washed away by development to form a solder mask pattern.

9. The PCB circuit copper thin-film plating process according to claim 8, characterized in that: The oil level of the screen cover is 1-2mm larger than that of the PAD and the single side of the line.

10. The PCB circuit copper thin-film plating process according to claim 8, characterized in that: The film exposure position is 0.05-0.10mm larger than the PAD and the single side of the line.

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