Process advances in plasma photoresist and residue removal with the use of H/sub 2/O vapor

Abstract

The benefits of H/sub 2/O-vapor, when added to a downstream plasma for post-via etch residue removal is discussed. This paper provides results of the polymer removal effectiveness of a FOx low-k post-via-etch application when H/sub 2/O vapor is added to the clean process plasma. Two significant findings are presented: (1) The importance of maintaining a low temperature during the residue removal step in order to prevent the 'hardening' of the residues, and (2) the benefit of using an intermediate plasma-free step that includes H/sub 2/O-vapor, for effective removal. Polymers were observed to separate from the sidewall during processes with the intermediate H/sub 2/O vapor step and rendered removable in a subsequent DI water rinse. This resulted in a significant enhancement of the yield, compared to the standard high temperature H/sub 2/O-vapor-free process of record.