CHEMICAL-MECHANICAL POLISHING IN SEMIDIRECT CONTACT MODE

In a typical chemical-mechanical polishing (CMP) process for interleve l dielectric planarization, the oxide removal rate is strongly depende nt on the parameters such as applied load, relative speed, and pad sur face properties. However, the experimental results presented in this w ork show that by maintaining a thin fluid film between the pad and the wafer and thereby reducing the role of the asperities in the pad, the oxide removal rate can be made independent of these polishing paramet ers. In this semidirect contact mode, the CMP process, carried out on 2 in. wafers, resulted in a uniform polish rate across the wafer, high run-to-run reproducibility, high selectivity between materials of dif fering chemical properties, and eliminated the need for pad surface co nditioning and in situ end-point determination equipment.