Dry etch processing in fan-out panel-level packaging - An application for high-density vertical interconnects and beyond

In this work, we demonstrate advances in plasma dry etch technology applied to common materials in semi-additive fineline processing for panel-level packaging. Emphasis is placed on deep reactive-ion etching into organic dielectric build-up materials as a scalable process for making vertical interconnects (vias). A capacitively coupled dual frequency plasma module was used for our experiments. We investigate the influence of different process parameters and gas mixtures on via shape, via sidewall quality and residue formation. To enable material-selective etching, a metallic hard mask is used, patterned by direct imaging lithography. For the removal of the hard mask we introduce a non-etching lift-off approach. Furthermore, a dry etch removal of sputtered Ti barrier and Cu seed layers is shown.