PRODUCTION OF MEDIUM FOR MAGNETO-OPTICAL RECORDING

摘要

PURPOSE:To permit easy and exact production of a magneto-optical recording medium having various film thickness gradients in the radial direction of a substrate by covering part of the substrate with a mask and sputtering an RE-TM alloy target while rotating the substrate, thereby forming a magneto- optical recording layer on said substrate. CONSTITUTION:The disk-shaped light transmittable substrate 3 is freely rotatably disposed to the position apart by a horizontal distance (x) and vertical distance (y) from the approximate center of the alloy target 1 consisting of the amorphous rare earth-transition metal alloy (RE-TM) and part of the substrate 3 is covered by the mask 4 having an aperture in the direction opposite from the alloy target 1. While the substrate 3 is rotated, the target 1 is sputtered and the alloy target material is deposited through the aperture on the substrate. The magneto-optical recording layer provided with the nearly specified film thickness gradient in the radial direction of the substrate is thereby easily and exactly obtd. Execution of satisfactory recording on both the inside and outside circumferences is thus permitted without having a need for changing the power and irradiation time of recording light with the inside and outside circumferences of the substrate 3.