International Business Machines Corporation

Hitachi Global Storage Technologies Netherlands B.v.

Hitachi Global Storage Technologies

Jon Edward Podolske

Steven L Maynard

Frederick Paul Benning

David C Paurus

James Aloysius Hagan

Douglas Howard Piltingsrud

Douglas Allan Kuchta

A self-cleaning colloidal slurry and process for finishing a surface of a glass, ceramic, glass-ceramic, metal or alloy substrate for use in a data storage device, for example. The slurry comprises a carrying fluid, colloidal particles, etchant, and a surfactant adsorbed and/or precipitated onto a surface of the colloidal particles and/or substrate. The surfactant has a hydrophobic section that forms a steric hindrance barrier and substantially prevents contaminates, including colloidal particles, from bonding to the substrate surface. The slurry is applied to the surface of the substrate while a pad mechanically rubs the surface. Subsequent cleaning with standard soap solutions removes substantially all remaining contamination from the substrate surface. In an exemplary embodiment, the slurry is used to superfinish a glass disk substrate to a surface roughness of less than 2 &#x212b;, with substantially no surface contamination as seen by atomic force microscopy (AFM) after standard soap cleaning steps.

Self-cleaning colloidal slurry composition and process for finishing a surface of a substrate

A polished glass disk is prepared for a magnetically recordable coating by texturing the surfaces with a highly abrasive material being abrasively engaged with the surfaces as the disk is rotated, thereby creating a relatively coarse texture with the abrasions concentric with the axis of rotation of the disk. Thereafter, the roughness of the texturing is reduced by abrading the surface of the disk with a polishing pad and an etchant slurry of colloidal silica. The etchant component has the property of attacking or softening the glass disk during the fine polishing with the colloidal silica slurry. As both the texturing step and the fine polishing step deposit a plurality of concentric abrasions on a glass disk, these abrasions aid in retaining the magnetically recordable coating deposited thereon to complete a magnetically recordable disk for use as a data storage member.

Process for producing glass disk substrates for magnetically recordable data storage disks

A method of preparing for a disk polishing operation includes providing a polishing machine having a first and a second superposed platen. A first polishing pad is on the first platen and a second polishing pad is on the second platen. A plurality of carriers are disposed between the first and second polishing pads. Each carrier is adapted to rotate relative to the polishing pads and is adapted to carry at least one glass disk. A pressure, temperature and rotational speed of the polishing machine used during a disk polishing operation are determined. A number of diamond disks are provided. A diamond disk is placed in respective ones of the carriers. The polishing machine is operated at or near the determined pressure, temperature and rotational speed while simultaneously dressing the respective surfaces of the polishing pads using the diamond disks.

Method of polishing disks

Disk substrates are polished in a process which uses a single load of the disks to a polishing apparatus and a single polishing slurry. Preferably, the process varies at least one polishing parameter at multiple stages to achieve both a reasonable rate of removal during one stage and a smooth finished surface during another stage. Preferably, a fine grit cerium oxide slurry is used, along with a polishing pad having surface characteristics intermediate those of relatively hard pads typically used for material removal, and of relatively soft pads typically used for fine finishing. The polisher operates at high pressure and speed during a material removal stage, and then reduces speed and pressure during a finishing stage to achieve a suitable surface finish, without removing and cleaning disks between the two stages.

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Plainview, MN, United States of America

Jon Edward Podolske