In the chemical-mechanical polishing (CMP) process, the pad conditioning density distribution plays a crucial role in the pad wear. A precise model and detailed analysis of a conditioning density function are required. To this end, at first we construct the mathematical model of polishing trajectories on the pad, then under the assumptions that the diamond grains are uniformly distributed and a slow sweeping motion is applied during dressing, the conditioning density distribution for a pad in CMP process is determined. This conditioning density function is verified through numerous numerical examples. In the mean time, it was also observed that to have a flat distribution of pad wear rate we have to make the ratio of disk-radius to pad-radius small, and the effect of the pattern of grain distribution on conditioning density function is insignificant, which agrees with known results from literature.
關聯:
IEEE Transactions on Semiconductor Manufacturing 20(4), 464-475
