Significant Improvement of Defect in CMP Process by Using Lower Retainer Ring Pressure

摘要

Effect of retainer ring pressure on defect performance in CMP(Chemical Mechanical Polishing) process was examined through experiments. As a result, it was proved that higher retainer ring pressure resulted in higher defect counts both in Oxide CMP and Cu CMP. Defect performance in Oxide CMP shows exponential relation to the retainer ring pressure. Whereas defect performance in Cu CMP shows linear relation to the retainer ring pressure. Furthermore, dependence of retainer ring material on defect in CMP process is also elucidated. Four kinds of material were used for these evaluations. Although the same polishing condition was applied to all samples, each sample showed different defect level. Relation between defect level and material property will be discussed.