Sputter metallization of plastic parts in a just-in-time coater

Abstract

The coating of plastic parts such as car head lamps, reflectors for lighting systems and decorative parts with a highly reflective metal layer nowadays is mostly done in big batch coaters using an evaporation technique. We introduce a new just-in-time coater in which only one piece is coated per cycle time. Typical cycle times of 33–56 s have been realized for coating reflector parts with an aluminium layer of 80 nm thickness. The deposition is done by magnetron sputtering. The advantages of this concept are small footprint of the coater, no need for big storage space for substrates, only a small number of substrate fixtures needed, in-line capability, ability to coat substrates of complex shape, deposition of materials with high melting point (e.g. Cr) and deposition of alloys (e.g. CuAl) and sintered material mixtures. For high productivity a new interpole target magnetron sputter cathode has been developed with extremely high target width, high deposition rate and high target lifetime of up to 50 000 coating cycles. The coater concept, the sputter magnetron, thickness distribution and throughput are discussed.