PCB blistering is caused by the copper plating process in the circuit board production process, and it is also one of the more common quality defects. Because of the complexity of the circuit board production process and process maintenance, especially in the chemical wet treatment process, it is difficult to prevent blistering defects on the board surface. The reason for the foaming on the PCB board surface is actually the problem of poor bonding force on the board surface, which can also be said to be a problem with the surface quality of the board surface;

1. Micro-etching in the pre-treatment of PCB copper sinking and graphic electroplating. Excessive micro-etching will cause the substrate to leak from the orifice, causing foaming around the orifice; insufficient micro-etching will also cause insufficient bonding force and cause foaming. Therefore, it is necessary to strengthen the control of micro-etching; in addition, the copper content of the micro-etch tank, bath temperature, loading capacity, micro-etch agent content, etc. are all items that should be paid attention to.

2. The activity of the PCB copper sinking solution is too strong. The copper sinking solution is newly opened or the content of the three major components in the bath is too high, especially the copper content is too high, which will cause the activity of the bath to be too strong, the chemical copper deposition is rough, hydrogen, cuprous oxide, etc. are too much contained in the chemical copper layer.

3. The surface of the PCB board is oxidized during the production process. If the sinking copper board is oxidized in the air, not only may there be no copper in the hole, the board surface is rough, but also the board surface may cause blistering; the sinking copper board is stored in the acid solution for too long, the board surface will also be oxidized, and this oxide film is difficult to remove; therefore, the sinking copper board should be thickened in time during the production process, and the storage time should not be too long.

4. PCB sinking copper rework is poor. Some sinking copper or graphics reworked boards have poor deplating during the rework process, incorrect rework methods, improper control of micro-etching time during rework, or other reasons will cause blisters on the board surface. If the sinking copper board is reworked online If the sinking copper is found to be poor, it can be directly removed from the line after washing with water, then pickled and reworked without micro-etching.

5. Insufficient water washing after development, too long storage time after development or too much dust in the workshop during the transfer process of PCB graphics will cause poor cleanliness of the board surface and poor fiber treatment effect, which may cause potential quality problems.

6. The pickling tank before PCB copper plating should be replaced in time. Too much pollution in the bath or high copper content will not only cause problems with the cleanliness of the board surface, but also cause defects such as rough board surface.

7. Organic pollution, especially oil pollution, in the PCB electroplating tank is more likely to appear in the automatic line.

8. In winter, it is necessary to pay attention to the fact that printed circuit board manufacturers are charged into the tank during the production process, especially the plating tank with air stirring, such as copper-nickel. For nickel tanks in winter, it is best to add a heated water washing tank before nickel plating (water temperature is about 30-40 degrees), so as to ensure that the initial deposit of nickel layer is dense and good.

In the actual production process, there are many reasons for the blistering of the pcb board surface. Different printed circuit board factory equipment technology levels may cause blistering due to different reasons. The specific situation should be analyzed in detail, and it cannot be generalized. The above-mentioned reasons are not divided into priorities and importance. The brief analysis is basically based on the production process. It is just to provide you with a problem-solving direction and a broader vision. I hope that it can play a substantive role in your process production and problem-solving.

-----------------------------------------------------------------------------

Source: circuit board PCB

Disclaimer: We respect originality and focus on sharing; the copyright of text and pictures belongs to the original author. The purpose of reprinting is to share more information and does not represent the position of the company. If there is any violation of your rights, please contact us in time, and we will delete it as soon as possible. Thank you