Investigation of pad surface topography distribution for material removal uniformity in CMP process

This paper investigates the pad surface topography distribution and its effect on material removal uniformity using two different types of conditioners in an interlayer dielectric chemical mechanical planarization (CMP) process. The two types of conditioners are a random diamond disk and a uniform diamond disk (UDD). The pad surface was roughened by using the two diamond disks, and then the surface roughness and real contact area between the pad and the wafer were analyzed. The UDD generated a more uniform surface layer having a low standard deviation, although it had a low surface roughness. The random roughness pad showed a low material removal rate with a wide standard deviation, but the uniform roughness pad demonstrated a high removal rate with a narrow standard deviation. The uniform roughness pad improved the wettability of the pad and uniform distribution of the slurry across the pad. Therefore, the uniform roughness pad gave a more stable polishing performance than the random roughness pad. (C) 2008 The Electrochemical Society.