DESIGN TIP: Pad Only Plating
This process is used on double sided (Type 2) circuits where maximum flexibility is desired. A full thickness of electrodeposited copper will reduce flexure life. Therefore in those cases, it is desirable to limit the amount of electrodeposited copper on the conductor surfaces.
The circuit panels are processed through normal processes up to and including the electroless copper plating process. The panels are electrolytic “flash” copper plated to thickness of .0004” maximum (see note below). Photoresist is applied with an image printed and developed that exposes the holes and a slight amount of the surface around the perimeter of the hole (typically .005-.010” around the hole). The panels are electrolytic “pattern” copper plated to increase the plating in the holes up to minimum specification requirements (typically .001” min.). The photoresist is stripped and reapplied to image the circuit pattern. The panels are processed through the remaining processes typical of Type 2 circuits.
For more information on DuPont™ Pyralux® Flexible Circuit Materials, please contact us or visit our website for additional regional contacts.