Method for removing carbon-rich particles adhered on the exposed copper surface of a copper/low k dielectric dual damascene structure

摘要

A method for removing carbon-rich particles adhered on the exposed copper surface of a copper/low k dielectric dual damascene structure is provided. A barrier layer and a barrier-CMP stopping layer are formed between the copper layer and the low k dielectric layer of the dual damascene structure. After a Cu-CMP process and a barrier CMP process are completed, a chemical buffing polishing process using a basic solution under a downward force of about 0.5 to 3 psi is performed to remove carbon-rich particles adhered on the exposed copper surface due to the low k dielectric having at least 90% carbon element being exposed and then polished during the Cu-CMP process and the barrier CMP process, which results from a dishing phenomenon of the copper layer occurring during the two CMP processes. Finally, a post chemical mechanical polishing cleaning process is performed to remove away dirt left on the exposed copper surface.