The hole breaking state is the phenomenon of point distribution instead of the whole circle opening. It is called "spot hole breaking", and some people call it "wedge hole break". The common causes are caused by the bad treatment of the removing slag process. The process of removing the slag from the circuit board will be carried out by the leavening agent, and then the corrosion of the strong oxidant permanganate will be carried out. This process will remove the slag and produce a microporous structure. After the removal process, the residual oxidant is removed by reducing agent, and the typical formula is treated with acid liquid.

Because the waste residue treatment will not see any residue problems, the industry often ignores the reduction of acid liquid monitoring, which may allow the oxidizer to stay on the hole wall. After the circuit board into the electroless copper, after the whole hole agent processing circuit board micro etching, then the residual oxidant again by acid soaking and let the resin stripping residual oxidizing agent area, and at the same time will destroy the whole hole agent.

The damaged pore walls do not react with subsequent PD colloids and chemical copper treatment, and these regions show a copper free appearance. If the foundation is not established, the plating copper will not be covered completely and the point hole will be broken. This kind of problem has already happened in many circuit board factories, and pay more attention to the process of reducing residue, and the monitoring of syrup should be improved.