In the process of PCB processing, it is inevitable that there will be defective products, which may be caused by machine errors or human factors. For example, sometimes there will be an abnormal condition called hole breaking state, the cause of which shall be analyzed on a case-by-case basis.
If the state of hole breaking is the phenomenon of point-like distribution rather than the whole circle breaking, it is called point-like hole breaking, and some people call it “wedge hole breaking”, which is often caused by poor treatment of the process of degumming slag. During PCB processing, the process of degumming slag production will first undergo the treatment of swelling agent, and then the erosion of the strong oxidant “permanganate”. This process will remove the gumming slag and produce microporous structure. Oxidants left over from the removal process are removed by reducing agents and typically treated with acidic liquids.
Since the residue of glue residue will not be seen after the treatment of glue residue, the monitoring of reducing acid solution is often neglected, which may leave oxidant on the pore wall surface. Then the circuit board into the chemical copper process, after the hole agent treatment of the circuit board will be micro-corrosion treatment, at this time the residual oxidant was soaked in acid and let the residual oxidant area resin peeling, but also equal to the hole agent destroyed.
The damaged pore wall will not react in the subsequent palladium colloid and chemical copper treatment, and there will be no copper precipitation in these areas. Without the foundation established, the electroplating copper cannot be completely covered and thus produces punctured holes. This kind of problem has occurred in many circuit board factories in the process of circuit board processing, pay attention to the process of degumption residue reduction steps of the potion monitoring should be able to improve.
We need to strictly control every link in the PCB processing process, because chemical reactions sometimes occur slowly in the corners that we do not pay attention to, thus damaging the entire circuit. We should be vigilant against such hole breakage.