Development of continuous high rate sputtering system for three layers of magnetic recording media with ultra high density.

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Co-Cr thin films prepared by sputtering process has been considered to be one of the most promising media for the perpendicular magnetic recording system, which is a theoretically advanced technology for the ultra high density recording and is expected to replace the conventional longitudinal magnetic recording system in the furture. For the practical realization of the perpendicular magnetic recording, the high rate sputtering system suitable for the media preparation has been strongly required. We have developed the Facing Targets Sputtering (FTS) system which is designed to be able to confine the high energy <gamma> -electrons in the space between the facing targets and promote the ionization of argon gas, even at the argon gas as low as <10゛(-4)> Torr order. Consequently, films can be deposited under wide range of argon gas pressure. The results of the films evaluation revealed that the microstructure of CoCr films are mainly dominated by the argon gas pressure during the film formation. Films prepared under the argon gas pressure lower than 1mTorr show that they are composed of fine polyhedral grains closely packed each other and the stacked up from the bottom to the top of the film. Thesefilms show excellent c-axis orientation and superior magnetic properties with compared to the films with the columnar structures, which are commonly observed among the films prepared by conventional RF diode sputtering system. Based upon these fundamental results, films were deposited using new FTS system which is capable to deposite three kinds of materials sequentially on the continuous tape substrate or on the disk substrate which is able to rotate up to 10,000 rpm during film deposition. Co-Cr tapes prepared by this new FTS system, for example, has shown excellent recording characteristics and the recording density of about 200 kBPI has been obtained.