アルミナ砥粒による磁気ディスク基板の高平滑ポリシングに関する研究 (第2報)

Abstract

This report aims to clear experimentally the influence of polishing pressure, polishing speed and the content of Al2O3 abrasives included in polishing fluid on the removal rate and the slight undulation of the NiP plated magnetic disk substrate. The substrate surface is examined by measuring the slight undulation and the surface roughness, which are measured on the substrate surface of 4 mm length with WYKO and 50 μm length with Talystep, respectively. The polishing experiments are carried out with a marketing machine with some reconstructions. In case of the soft type polisher, the removal rate increases with the increases of polishing pressure, polishing speed and the content of Al2O3 abrasives. The terminal surface roughness becomes better for lower polishing pressure. Polishing speed and the content of Al2O3 abrasives have little influence on the terminal surface roughness. The terminal slight undulation becomes better for lower polishing pressure and the less content of Al2O3 abrasives, and is little influenced by polishing speed. In case of the hard type polisher, on the other hand, the removal rate increases little or decreases with the increase of polishing speed over a critical polishing speed at low pressure because the floating force of polishing fluid decreases the actual polishing pressure. The relationship between the polishing conditions and the slight undulation for the hard type polisher, however, is similar to the soft type polisher. The best slight undulation obtained in the experiment is about 4 nm (P-V value).