Characterization and Simulation of Pattern-Dependency in ECP Topography

Abstract

Electronic Copper Plating (ECP) topography is known affected by layout design and dummy inserting. With different electroplate liquid, copper can be filled in the trench by the forms of conformal-fill, bottom-up or supper-fill. Such post ECP topography not only depends on process conditions, but also exhibits strong pattern-related dependency. Here, pattern-related effects of ECP topography were characterized with a pre-designed test chip that contains test-keys of line/space arrays of varying line and space widths, and varying pattern-density (PD). It was shown that: 1) Fixed PD at 50%, the characteristics of test features array height (AH) and Step-height (SH) are strongly associated with line-width (LW). 2) Fixed LW, different trends were observed for narrow lines and wide lines, in both AH and SH vs. varying PD. A semi-empirical model was built to simulate post-ECP topography. It captured all key pattern-dependency in post-ECP AH and SH with acceptable fitting GOF (R2>90%).