Polish rate and corresponding pad surface morphology data are presented for oxide polishing over a range of process conditions with fumed and solution grown silica slurries, utilizing a range of pad conditioners representing different levels of aggressiveness. Pad surface data are obtained using vertical scanning optical interferometry. The pad surface morphology is highly responsive to process conditions, slurry type and the aggressiveness of pad conditioning. Under some conditions, significant deviations from idealized polish behavior are observed. The most significant deviations from idealized polish behavior correspond to pad surfaces exhibiting the highest degree of surface asperity deformation as indicated by changes in the pad height probability distribution. A fumed silica slurry induces more significant changes in the pad height probability distribution than a solution grown silica slurry at an equivalent process condition, and exhibits correspondingly more extreme deviations from idealized polish behavior. These data can be interpreted in the context of a hydrodynamic model based on the contact mechanics at the pad wafer interface and the fluid properties of the slurry.
展开▼
