Novel Copper Barrier Slurry for Advanced Cu CMP Process

Inhalt:
Lower defectivity, pattern loading effect and better stability of removal rate (RR) through soft pad polishing life time have been identified as key influencing factors in copper CMP process. In order to meet the strict requirement, novel copper barrier slurry is designed and developed as a consequence. One of the biggest issue of soft pads in Cu barrier CMP process is that it tends to suffer serious RR trending through pad life. To overcome the problem faced, a chelator was added to LK slurry to improve RR stability and adjustable selectivity for process demanded. In addition, it is well-known that scratch and organic residue often have a significant but negative effect on yield and the following topography. As developing LK slurry, the design concept is to improve defectivity at the same time. With the usage of high purity abrasive and the optimal concentration of Benzotriazole (BTA) as Cu inhibitor and concentration of Cu suppressor, the defectivity and loading effect will be greatly improved compared with standard commercial slurry A. In this paper, the performance of LK slurry not only meet the difficult criteria of Cu barrier process but also present much more steady performance through the entire pad life. Keywords: CMP, Chemical mechanical Polishing, Selectivity, Defectivity, Stability, Advanced copper barrier slurry, LK slurry