DRY ETCH CHALLENGES OF 0.25 MU-M DUAL DAMASCENE STRUCTURES

This paper investigates the influence of etch process parameters on th e geometry of dual damascene patterns. Etch residues and a via taper a re found to depend strongly on antireflection coating (ARC) etch time and O-2 flow. Furthermore, they have significant impact on the metal f ill. ARC residues and polymer formation during the interconnect line e tch are identified to be responsible for the observed features. Using an optimized etch a dual damascene process has been integrated into 0. 25 mu m three metal level structures.