Development of a Plasma Etching Process of Copper for the Microfabrication of High-Density Interconnects in Advanced Packaging

Current microfabrication approaches face many challenges when scaling down to form copper lines of less than 2 µm line/space width on organic substrates. In this work, a one-step Ar/H2/Cl2 plasma etching process has been developed, allowing to replace wet etching in the semi-additive process (SAP) approach. By optimizing the etch process, we demonstrate the fabrication of high-density copper-based RDL with a L/S of ~1.65 µm on a packaging substrate