MASS PRODUCTION OF HIGH PERFORMANCE MAGNETO-OPTICAL DISKS BY IN-LINE SPUTTERING PROCESS

Using an in-line sputtering system composed of seven chambers and one outgassing module, the effects of sputtering conditions on the performance and reproducibility of Magneto-Optical disks based on TbFeCo have been studied. A dc reactive sputtering superimposed with an ac has remarkedly reduced arcings in the fabrication of silicon nitride films without excessive substrate heating. The influences of total pressures, Ar/N2 ratios and input powers on the refractive index of a silicon nitride film were extensively investigated. The protective ability of a silicon nitride film was found to be mainly dependent on the refractive index, but an amount of the warp of polycarbonate substrates was dependent on the process parameters. The influences of sputtering conditions on the corrosion resistance and magnetic properties were also studied. Good uniformities of the thickness and composition of a silicon nitride layer and a magneto-optical layer could be achieved by sputtering at a low pressure. An excellent reproducibility in fabricating the disks having a quadri layered structure was achieved and BER was at the low level of 10-6.