Chemical-Mechanical Polishing of NiP Alloy for Hard Disk Drive Substrates

In this study, the velocity field and the polishing track on the disks for the chemical-mechanical polishing (CMP) process have been simulated, and their effects on material remove rate (MRR) and surface parameters of a polished disk are discussed. The mechanical effects of two slurries (Slurry A and Slurry B) with different abrasive size distribution on the polishing properties and the surface parameters as well as the mechanisms are also studied. An ultra-smooth surface has been achieved with both Slurry A and Slurry B. Average roughness (Ra) by AFM is about 0.11 nm for Slurry A with broad abrasive size distribution, and about 0.09 nm for Slurry B with narrow abrasive size distribution.