Reducing time dependent line to line leakage following post CMP clean

Abstract

A systematic approach was taken to identify methods to prevent post CMP corrosion of copper in 22nm interconnect structures. Line to line current leakage measurements (at various times post CMP) were used as a means to quantify the extent and time-dependence of copper corrosion. Interruption of the corrosion mechanism by the use of passivating agents in post-CMP clean chemistries is explored. A broad-based screening was conducted to identify aqueous formulations of passivating agents for protection of copper which do not have deleterious effects on line resistance and overall defectivity. A formulation was identified which was effective in preventing corrosion when applied during post CMP brush clean. © 2010 Materials Research Society.