The printed circuit board, or “PCB” industry has been using screen printing as a valuable part of their manufacturing process for over 50 years.
Although there are other technologies competing with screen printing in the PCB industry, screen printing is still the most economical and fastest way to print PCB solder masks etch resist, legends and single multi-layers.
Introduction
Printed circuit boards begin as a thin layer of copper that is bonded to a substrat (fiberglass/resin, PTFE, ...). The copper surface is printed with an etch resistant layer that covers the desired, resulting circuitry pattern. During the etching process, the copper is removed in areas that are not printed, leaving the desired circuit pattern behind in copper.
The etch resist layer is removed, and a solder mask layer is screen printed over the copper circuitry-strategically revealing the component solder pads. After the solder mask layer has been dried and cleaned, the PCB “legend” (any required text, symbols or artwork required for manufacturing) is screen printed.
The PCB is complete after the hole drilling, circuit testing, and chemical cleaning processes have been performed. The process mentioned above is only for single side printed circuit boards-the entire process may be duplicated or repeated at various stages when manufacturing double-sided or multi-layer PCB applications.
Screen Printing Process
Screen printing printed circuit boards is typically performed in a clean, dust-free room using semi-automatic or fully-automatic screen printing presses. The most common PCB panel size is 53 x 72 cm, with the printing area around 50 x 70 cm. The printed panel may contain many PCB panels that are printed at once, and will eventually be separated.
Screens are stretched with precision, stable polyester meshes like SEFAR PME and SEFAR PMCE, two meshes specifically engineered by Sefar for competitive electronic printing. Solvent and/or UV pastes are used for printing the etch resist patterns, plating resist patterns and solder masks. Specially formulated solvent inks are used for legend printing.
