Unexpected Enhancement of Aluminum Etching Rate by Increased Nitrogen Concentration in Semiconductor Manufacturing

Aluminum interconnects are critical in the production of large-scale integrated circuits, with aluminum metal etching being a key processing step. Here, we report that increasing the concentration of nitrogen—traditionally used as a protective gas during aluminum etching—enhances the etching rate unexpectedly. We have systematically investigated the effect of nitrogen concentration on the etching rate under varying pressures and etching temperatures. Furthermore, we propose two potential mechanisms to explain this phenomenon: one involving enhanced Cl₂ dissociation facilitated by excited nitrogen species, and another involving the reduction of polymeric residues through active nitrogen radicals. These findings offer key insights into optimizing aluminum etching strategies, thereby enhancing semiconductor manufacturing efficiency and quality.