Dielectric bottom anti-reflective coatings for copper dual damascene interconnects

Abstract

This paper presents a study on the patterning of low-κ organosilicate (SiOC:H) film stacks in a copper/low-κ interconnect integration process using silicon oxy-nitride films (SiOxN y) as dielectric antireflective coatings (DARC). A comparative study of lithography performance of single layer SiOxNy DARC, dual layer SiOxNy DARC and the conventional organic bottom antireflective coating (BARC) was carried out by both simulation and experiment to determine the most suitable antireflective coating for the 'via first dual damascene' (VFDD) process. It is found that at 248 nm exposure wavelength, the dual layer DARC is the most effective for the reflectivity control of low-κ SiOC:H film stacks. A process integration scheme incorporating the dual layer DARC in the VFDD scheme has been proposed. The advantages of the proposed scheme for dual damascene process integration are demonstrated. © 2003 Elsevier B.V. All rights reserved.