Magneto-optical Disk Substrate Prepared by Reactive Ion Etching

Guide tracks of 1.6μm pitch, 0.70.8μm width and 0.07μm depth were prepared on a glass disk by reactive ion etching technique. Etching rate became high and a smooth etched surface was obtained according to the decrease of CHF3 gas pressure and the increase of a self bias voltage induced to a cathode. It was found that the pregrooved glass substrate prepared under the CHF3 pressure of 0.3 Pa and the self bias voltage of -500V had sufficient performance required for magneto-optical memory application.