What Are The Reasons For Circuit Board Blistering?

During the production process, there will be blistering of the circuit board due to various reasons. So what are the specific reasons for this?

First. Defective copper brush plate:

Excessive pressure on the front copper grinding plate causes deformation of the orifice, brushes out the copper fillet of the orifice, and even leaks the base material. This will cause blistering of the orifice during the process such as electroplating tin spraying and soldering. The plate does not cause leakage of the substrate, but an excessively heavy brush plate will increase the roughness of the copper at the orifice. Therefore, during the micro-etching and roughening process, the copper foil is likely to cause excessive roughening, and there will also be a certain quality. Hidden dangers; therefore, attention should be paid to strengthening the control of the brush plate process. The process parameters of the brush plate can be adjusted to the best through the wear scar test and the water film test.

Second, the problem of substrate processing

For some thinner substrates (generally below 0.8mm), because the substrate is poor in rigidity, it is not appropriate to use a plate brush to brush the plate. It may not be possible to effectively remove the protective layer specially treated to prevent oxidation of the copper on the surface of the substrate during the production and processing of the substrate. Although this layer is thinner and the brush plate is easier to remove, it is more difficult to use chemical treatment. It is important to pay attention to control so as not to cause the problem of blistering on the surface caused by the poor bonding force between the substrate copper foil and the chemical copper; this kind of problem will also cause the blackening and browning failure when the thin inner layer is blackened. , Color unevenness, local black browning is not good.

Third, the board surface is oxidized during the production process

If the immersed copper plate is oxidized in the air, not only may there be no copper in the holes, the surface of the plate may be rough, but it may also cause the surface of the plate to blister; if the copper plate is stored in the acid solution for a long time, the surface of the plate will also be oxidized, This oxide film is difficult to remove; therefore, the copper plate should be thickened in time during the production process, and it should not be stored for too long. Generally, the copper plating should be thickened within 12 hours at the latest.