Study of Process for Forming Microscopic Surface Bumps with Ultra-fine Particles

Abstract

Flying height of magnetic head in hard disk drives has been markedly reduced in proportion to an increase in recording density, resulting in a large head-disk stiction. One of the techniques for overcoming this problem is to use laser texturing. The laser can create bumps with a typical height of 20-30nm and a diameter of 10μm, although a smaller bump diameter is needed to obtain better tribological performance. We therefore studied a precise bump-diameter control process with ultla-fine particles (UFPs) of SiO₂ and a dry etching process. UFPs of 0.3μm diameter were coated on a disk surface by dipping or an ink-jet method, and the surface was etched by oxygen. After removing the UFPs, the formed bumps were measured to have a height of 10-20nm and diameter of 0.21μm. The diameter were about the same as the UFP diameter.