What are the reasons for the foaming of the copper plated surface of the circuit board

The blistering of the board is one of the more common quality defects in the production process of the circuit board. Because of the complexity of the production process of the circuit board and the complexity of the process maintenance, especially in the chemical wet processing, the prevention of the blistering defects on the board surface is compared. difficult. Next, let's analyze what causes this phenomenon.

1. The problem of substrate processing; especially for some thin substrates (generally 0.8mm or less), because the substrate is poor in rigidity, it is not suitable to use a brush to brush the board, which may not effectively remove the substrate production and processing. In the process, in order to prevent the oxidation of the copper foil on the board surface, the protective layer is specially treated. Although the layer is thin, the brush plate is easy to remove, but there is a great difficulty in chemical treatment, so it is important to control the production and processing, so as not to cause the board surface. The problem of blistering of the board caused by the poor bonding force between the substrate copper foil and the chemical copper; this problem also occurs when the thin inner layer is blackened, and there is also blackening and browning, uneven color, and partial black brown. Can not be equal to other issues.

2. The surface of the board is contaminated by oil or other liquids caused by machining (drilling, laminating, milling, etc.).

3. Poor copper plate: The pressure of the plate before the copper sink is too large, causing the hole to deform and brush the copper foil round hole or even the hole to leak the substrate. This will cause the copper plating and soldering process. Foaming of the orifice; even if the brushing plate does not cause leakage of the substrate, the excessively heavy brushing plate will increase the roughness of the copper of the orifice, so that the copper foil is likely to be excessively coarsened during the microetching roughening process. There will also be certain quality hazards; therefore, it is necessary to pay attention to the control of the brushing process. The process parameters of the brushing plate can be adjusted to the best through the wear scar test and the water film test.

4. Washing problem: Because the copper plating treatment is subject to a large amount of chemical syrup treatment, all kinds of acid-base and non-polar organic solvents are more, and the surface of the board is not cleaned, especially the copper-adjusting degreaser will not only cause cross-contamination. At the same time, it will cause partial treatment of the board surface or poor treatment effect, uneven defects, causing some problems in bonding; therefore, it is necessary to pay attention to strengthen the control of water washing, mainly including cleaning water flow, water quality, Control of washing time, and dripping time of the board; especially in winter, the temperature is lower, the washing effect will be greatly reduced, and more attention should be paid to the control of washing.