Cu-CMP Process Development for Cu/ultra-low k (K～2.2) materials

摘要

Using two Cu slurries and a new barrier slurry (66XX-series), two different CMP process approaches were investigated. Tunable 66XX series barrier slurry was modified selectivity of required Cu to Ta removal rate. Selectivity. As a result of this, fang's issue is resolved in the dishing profile. CMP Process approach 1 with Commercial Cu slurry and the 66XX series barrier slurry was developed. In order to further improve the dishing, a new chemically active Cu slurry 6XXX series was introduced at the over-polishing step and polishing process (CMP approach 2) was demonstrated successfully. These two processes were used for Cu/ ultra low k materials (K～2.2) and the performance was found to be better good if the new CMP process approach 2 was used.