Production method for tin targets used in magnetron sputtering coating of glass

摘要

The tin material employed for coating glass surfaces with tin oxide (SnO) via 'magnetron sputtering' technique has to be joined onto a carrier copper backing plate for service use as it heats up during the process and therefore cannot carry its own weight. The tin slab piece is joining onto copper plate by creating a metallurgical bond, and the tin side of the copper-tin metallic couple named 'target' is consumed during the coating process. A new method for manufacturing of these copper-tin couples is described here.In today's technique, the manufacturing of the said 'target' metal couples is either achieved by casting the tin on a copper slab and solidifying it there, or by applying liquefied indium onto the necessary bonding area on the heated copper piece and afterwards placing the tin on that area thus forming a metallurgical bonding between the two metals.;The method proposed here is based on placing a foil made of an indium-tin alloy between the copper and tin slabs and forming a metallurgical bond at temperatures where this binding agent alloy melts. By using a foil and indium-tin alloy instead of molten indium alone a homogeneous quantity of binding agent can be employed at the interface, an economic saving achieved due to reduction of use of pure indium, and lesser diffusion of indium as a contaminant into the tin side of the copper-tin couple that is to be used in coating glass thus reducing the contamination in the tin oxide coating itself. Since the tin contamination is reduced, the contamination of the unconsumed scrap portion of the tin slab that is machined off the copper surface, as the tin slab cannot be exhausted entirely in the process, is also reduced.