Environmentally friendly dry de-smear of fine-via by ultra high density nonequilibrium atmospheric pressure plasma

A new approach of de-smearing fine via bottom residue is proposed in this study for high density package substrate manufacturing. 60 Hz nonequilibrium atmospheric pressure plasma was used as the plasma source, and perfluoromethyl vinylether (PMVE) was used as reactive gas for the dry de-smear evaluation. It was found that 2.0% of PMVE mixing ratio to the discharge gas (Argon) was enough to remove the via bottom residue including resin and silica filler. 60 Hz nonequilibrium atmospheric pressure plasma is vacuum chamber free and does not require high cost voltage source. The global warming potential (GWP) of PMVE is very low. Therefore, this approach is expected to be low cost and environmentally friendly dry de-smear technology for fine via of high density package substrate of next advanced generation.