Dual Damascene process for 500nm RDL using high-resolution photosensitive polymer

Abstract

This paper investigates the dual polymer damascene process for the Redistribution Layer (RDL), focusing on the fabrication of lines and vias with dimensions as small as 500nm. This corresponds to an RDL line pitch of 1000nm and a via-to-via pitch of 2000nm. The optimization of RDL lithographic process steps, achieved through the integration of a novel polymer, is presented in detail. These optimized processes enable the formation of functional M1-VIA1-M2 chains, with up to 450 blocks successfully fabricated at dimensions of 500nm, 700nm, and 1000nm. The scaling of both RDL lines and vias is approaching the standard 400nm dimensions commonly employed in silicon interposers.