Development of a Cu and W Compatible PERR Clean in BEOL Advanced Interconnect Patterning

Abstract

Low-k integration for 22 nm ½ pitch technology requires continuous development of compatible cleaning processes. In this paper the use of acidic (pH:0.5-3) and alkaline (pH:8-13.5) aqueous based chemistries are demonstrated for the removal of post-etch residues after low-k etch and the aim to remove the TiN HM. These chemistries are also compatible with W and Cu, respectively. At the same time, no decrease in CD was observed, which means that the exposed low-k material was not attacked by the cleaning processes used.