As suggested in U.S. Pat. No. 3,979,273 to Panzera et al, it is well known to sputter deposit both sides of a substrate by rotating the substrate between targets in the vacuum chamber. The substrate is in the shape of a cylinder which therefore requires that the substrate be rotated during the deposition process. There is no disclosure in this patent of a means for depositing on both sides of a substrate at one time without rotation by supporting a substrate through the center of the cathode targets.
U.S. Pat. No. 3,741,996 to Urbanek et al suggests a cathode/target that is larger than the substrate to be coated. This patent to Urbanek et al is typical of the prior art where the substrate is supported by a platform table which supplies the cooling and power for operation of the sputter deposition. The substrate is not rotated during the deposition process but only one side of the substrate is coated at one time because of the supporting table covering the second side of the substrate. Further, the substrate is not supported through the center of the cathode/target nor is it apparent from this patent how the support could be accomplished.
U.S. Pat. No. 4,073,262 to Scheffel et al suggests apparatus for the manufacture of magnetic coating of magnetic disks consisting of a means for coating both sides of a disk by spraying the coating material onto both sides of the substrate at one time. The substrate is supported by a ram extending from the center of a cover disk which prevents the sprayed material from escaping into the atmosphere.
The cover plates also provide an aerodynamic effect on the spreading of the dispersion over the disks during a spinning operation. The patent does not discuss the apparatus that would be involved in the sputter deposition of a similar substrate. There is no teaching in the patent how a substrate could be supported from the center of a cathode/target to accomplish a sputter deposition of both sides of the substrate without revolving the substrate.
U.S. Pat. No. 3,189,535 to Webb suggests a dual cathode target system for coating a spherical substrate. The sphere is supported on one end and rotated within for complete coverage. There is no disclosure of a means for supporting the substrate by way of the support from the center of the cathode target for even coating.
An IBM Technical Disclosure Bulletin entitled "Coating Magnetic Storage Disks," April 1969 at page 1611 discloses apparatus consisting of two plain parallel cathodes between which a magnetic disk substrate is located affixed to a rotating anode turntable. There is no showing of the apparatus by which the dual coating is attained and it does not appear that the substrate is supported parallel to the two parallel cathodes.
U.S. Pat. No. 3,878,085 to Corbani; Chapin, The Planar Magnetron, Vacuum Technology Research/Development, January 1974, pages 37-40; and Cormia et al, Magnetically Enhanced High-Rate Sputtering, Proceed. ElectroChemical Soc., September 1974 are of interest with respect to magnetically-enhanced sputtering.