Via² an ultra fine line concept for IC substrates developed by Atotech is based on recessed circuitry. Recessed circuit patterns are generated from the dielectric substrate by means of laser ablation.

The process eliminates conventional dry film or liquid resist based photolithography.
Recent advances in eximer laser technology enable line space resolutions in the order of 10µm to 8µm. Subsequent PTH, e’less copper and electrolytic Cu plating steps turn the trenched patterns into copper circuitry.
A final planarization process levels filled circuits and dielectric surface flash.

Schematic Comparison of Via² Process to SAP (Semi-Additive-Process):