CMP Evaluation of Reusable Polishing Pad using Auxiliary Plate

At present time, the most of polishing pads used by CMP (Chemical Mechanical Planarization) process are disposed of industrial waste without being reprocessed after use. In order to reprocess these old polishing pads, the auxiliary plate was developed and commercialized by TOHO Engineering Co., Ltd. in Japan. The polishing pad is stuck on the auxiliary plate: this plate can be easily placed and removed several times on polisher platen. By using the auxiliary plate, the surface and the grooves on the old polishing pad can be regenerated like a new polishing pad. The surface is leveled flatly by a cutting tool, and the grooves are redone as original by cutting deeper ones over the existing grooves. However, the removal of material from the wafer is dependent upon the surface properties of the polishing pad along with other process conditions. The polishing performances of the reusable pads were evaluated on Applied Materials(r) RefleXionTMLKTM polisher, through removal rate (RR), within wafer non-uniformity (Nu%), planarization efficiency and defects levels and showed similar results compared to the ones of a new pad. Keywords: Chemical Mechanical Planarization, Reusable polishing pad, Auxiliary plate.