In order to meet customer requirements, the plugging of circuit board via holes has evolved from traditional aluminum processes to using a stable and reliable white mesh for completing surface solder mask and plugging. Via holes are essential for interconnection and conduction in PCBs, and the demands of the electronics industry have spurred the need for advanced manufacturing and surface mount technologies.
Several requirements must be met for via hole plugging technology. This includes ensuring that the via hole contains only copper and can be either plugged or left open by the solder mask. If tin and lead are present in the via hole, there are specific thickness requirements (4 microns), with no solder resist ink entering the hole to avoid hidden tin beads. The via holes must be opaque with solder resist ink plugs, without tin circles, tin beads, or leveling requirements.
The trend of electronic products towards “light, thin, short, and small” has led to the development of high-density and high-difficulty PCBs. Consequently, a growing number of SMT and BGA PCBs require plug holes for mounting components, serving five key functions: preventing tin from causing short circuits during wave soldering, facilitating BGA soldering, avoiding flux residues, preventing virtual soldering and affecting mounting, and preventing solder balls from causing short circuits.