Rigid magnetic recording media are used for recording and retrieving digital data in computer disc drive devices. During fabrication of thin-film magnetic recording discs, hereinafter magnetic discs or discs, there are two important handling requirements that must be met in fabricating high quality discs. First, the work area must be free of contaminants, such as dust and other air-borne particles; second, the discs must be protected from physical damage that may occur as the discs are being handled.
A disc, after loading into a sputtering apparatus, travels through a series of sputtering chambers, or deposition stations, for deposition of successive layers onto the disc. In one type of sputtering apparatus, the disc is transferred from one sputtering station to another by means of a walking beam arrangement. The disc is balanced in a holder having a series of V-shaped receivers, typically three, that are arranged to receive and support the disc in a vertical position between opposing sputtering targets, for layer deposition on opposite sides of the disc. The V-shaped receivers must be deep enough to provide stable disc seating, and wide enough to present a substantial landing zone for the disc, as the disc is transferred in and out of the holder.
The groove width and depth of such V-shaped receivers is typically between 90-130.degree., and while less obtuse angles provide greater stability, the V-shaped receiver masks a portion of the disc. The masking produces disc shadowing effects in the outer tracks of the disc, reducing the effective bit storage space on the disc. There are also problems with discs tending to fall out of the V-shaped receivers or to vibrate during transport, creating damage to the edge of the disc. Further, when a bias is applied to the disc during sputtering, by applying a voltage to the holder, accumulation of material in the V-groove can become a secondary target source of deposition onto the disc in the outer track region, creating anomalies in the disc's surface.
It would be desirable, therefore, to provide for use in a sputtering system, a support and transport apparatus designed to stably hold a disc during sputtering, while reducing shadowing effects and therefore, increasing the effective storage space on the disc and generally improve disc transport stability.