The board surface of the circuit board is the surface binding force foaming problem of the poor, and then extended surface quality problem is the board, which includes two aspects:
1. surface cleanliness problems;
2. the problem of surface micro roughness (or surface energy).
All of the circuit board surface bubble problem can be reduced to the above reasons.
Binding force between the coating is bad or too low, in the subsequent production process and assembly process to produce resistance in the process of production and processing of coating stress, mechanical stress and thermal stress, resulting in different degrees of separation coating.
This may be in the process of production and processing factors caused the poor surface quality are summarized as follows:
1. substrate processing problems:
In particular, some of the more thin substrate (generally less than 0.8mm), because the substrate stiffness is poor, it is not appropriate to use the brush plate.
This may not be able to effectively remove the substrate in the process of production and processing to prevent surface oxidation of copper foil special treatment of the protective layer, the layer is thin, the brush plate is easy to remove, but it is difficult to use chemical treatment, so in the production and processing of important attentional control, so as to avoid the surface between the substrate and the adhesion of electroless copper foil due to poor surface bubble problem; the problem of blackening of the thin inner layer, there will be a black brown, uneven color, dark brown local first-class problem.
2. surface in machining (drilling, laminating, milling) process caused by oil or other liquid from dust pollution surface treatment bad phenomenon.
3. sink copper brush plate bad:
The copper deposition before grinding plate pressure is too large, resulting in deformation of the orifice orifice orifice or brush copper fillet leakage substrate, this will result in the deposition of copper plating hole foaming phenomenon in the process of spraying tin welding; if the brush plate did not cause leakage of the substrate, but the heavy brush plate will increase the roughness of the copper orifice, and in the micro in the process of the corrosion of rough copper foil is prone to excessive coarsening phenomenon, there will also be some quality problems; therefore should pay attention to strengthen the control process through the brush plate, wear test and test the water film parameters adjusted to the best political brush plate;
4. washing problem:
Because of heavy chemical copper plating process after extensive processing all kinds of organic solvent such as acid-base non-polar drugs more surface water net, especially heavy oil remover copper adjustment, will not only cause cross contamination, but also will cause the local treatment effect is not good or bad surface treatment, defects of uneven, causing some the binding force of problems; therefore should pay attention to strengthening the control of water, including the cleaning water flow, water quality, washing time, control panel and drop time etc.; low temperature in winter, the washing effect will be greatly reduced, more attention should be paid to the strong control of washing;
5. surface oxidation occurred in the production process:
Such as heavy copper in air oxidation, not only may cause the hole without copper, surface roughness, may also cause surface blistering; copper sink long time storage in acid solution, the surface will be oxidized, and the oxide film is difficult to remove; therefore, in the production process of copper plate to thicken. Not for a long time, generally at the latest within 12 hours after plating to thicken;
6. the organic pollution in the plating tank, especially the oil pollution, is more likely to appear in the automatic line;
7.Should pay attention to the timely replacement of acid copper plating bath , too much pollution in the tank, or the copper content is too high, will not only cause the surface cleanliness, can also cause defects such as surface roughness;
8. in addition, some factories in the production of bath in winter without heating conditions, but also to pay special attention to the production process of charged plate into the groove, especially bath air mixing, such as copper and nickel; nickel in nickel plating for cylinder winter best add warm water before washing tank (water temperature at about 30-40 degrees) the initial deposition of nickel layer, ensure good tight.