Detection of surface defects by optical inline metrology during Cu-CMP process

摘要

An efficient method of detecting defects in metal patterns on the surface of wafers. Embodiments include forming a metal pattern on each of a plurality of wafers, polishing each wafer, and analyzing the surface of the metal pattern on each polished wafer for the presence of defects in the metal pattern by analyzing an optical across-wafer endpoint signal, generated at the endpoint of polishing. Embodiments include determining the location of defects in the metal pattern by determining the position of non-uniformities in the optical-across-wafer endpoint signal.

主权项

1. A method comprising:
forming a metal pattern on each of a plurality of wafers; polishing each wafer; for each wafer, determining the endpoint of polishing by: periodically measuring the reflectance of the wafer surface during polishing; and receiving an optical across-wafer endpoint signal when the reflectance reaches a predetermined level; analyzing the surface of the metal pattern on each polished wafer for the presence of defects in the metal pattern by analyzing the optical across-wafer endpoint signal, generated at the endpoint of polishing; repeating the steps of polishing each wafer, determining the endpoint of polishing, and analyzing the surface of the metal pattern on each polished wafer for defects, for each subsequent wafer of the plurality of wafers until a defect is detected; and stopping polishing of the remaining wafers of the plurality of wafers once a defect is detected.