PRODUCTION OF MAGNETIC RECORDING MEDIUM

PURPOSE:To produce the magnetic recording medium having high reliability by uniform etching by covering and masking the inner peripheral hollow parts of the medium with a conductive material and generating plasma between a medium support and a counter electrode, thereby etching the surface layer. CONSTITUTION:The electrode 2 is disposed to face a substrate mounting holder 1 for holding the substrate 5 in a vacuum chamber and electricity is fed from an external power source (not shown in the figure) to this holder 1 to generate the plasma between the holder 1 and the above-mentioned counter electrode. The surface layer of the thin film on the substrate 5 is etched in this way to form the magnetic recording medium. The substrate masks 4 consisting of the conductive material covering the inner peripheral hollow parts of the substrate 5 are mounted to said parts in the above-mentioned production of the magnetic recording layer. The above-mentioned plasma is uniformly generated in this way, by which the distribution of the etching quantity is uniformized and the thin film magnetic disk having the high reliability is obtd.