PCB circuit board processing process will inevitably encounter several defective products, there may be caused by machine errors, there may be man-made reasons, for example, sometimes there will be a known as the hole break state abnormal situation, Specific circumstances of the specific analysis.
If the hole break state is a dot-like distribution rather than the whole circle of the phenomenon of breaking, known as the punctate hole broken, it was called "wedge hole broken." Common causes are due to the poor handling of the process. PCB circuit board processing in addition to the residue process will be the first leavening agent treatment, followed by strong oxidant "permanganate" erosion operations, this process will remove the glue residue and produce structure. After the removal process of the residual oxidizer, rely on the removal of the agent, the typical formula using acidic liquid treatment.
As the glue residue treatment, and will not see the problem of residue residue, we often ignore the monitoring of the reduction of acid, which may allow the oxidant to stay in the hole wall. After the circuit board into the chemical copper process, after the whole agent treatment circuit board will be micro-etching treatment, then the residual oxidant again by acid soaking and let the residual oxidant zone resin peeling, but also equal to the destruction of the hole agent.
The damaged pore walls do not react in the subsequent palladium colloid and chemical copper treatment, and these areas exhibit copper-free precipitation. The foundation is not established, electroplating copper, of course, can not be completely covered and produce punctured hole broken. This problem has been in a lot of circuit board factory in the circuit board when the time has occurred, pay more attention to the process of reducing the process of removing the dregs Potion monitoring should be able to improve.
PCB circuit board in the process of processing every step we need to strictly control, because the chemical reaction will sometimes we do not pay attention to the corner slowly occurred, thus undermining the entire circuit. This hole to break the state we should be vigilant.
PCB board appearance
Bare boards (no parts on top) are also often referred to as "Printed Wiring Board (PWB)". The board itself is made of insulated and non-bendable material. On the surface you can see the small line material is copper foil, the original copper foil is covered in the entire board, and in the manufacturing process part of the etching process, the remaining part of the network into a small line The These lines are called conductor patterns or wiring and are used to provide circuit connections for parts on the PCB.
Usually the color of the PCB board is green or brown, which is the solder mask (solder mask) color. Is insulated protective layer, can protect the copper wire, but also to prevent short-circuit caused by wave welding, and save the amount of solder. In the solder layer will be...