eral other ways. In some coating applications, higher deposition rates are preferred. This requires both a higher machine throughput (achieved through higher power levels) and an increased coating capacity. For planar targets, the use of higher power levels is not always possible because the target material can melt or crack under the thermal load. In rotating cylindrical targets, the thermal load is uniformly distributed over the complete circumference of the target, resulting in much more efficient cooling of the target tube and the ability to use higher power densities.
Rotating cylindrical targets also offer a higher coating capacity compared to a similar standard planar target. This is due to the higher target utilization of the rotating cylindrical target, as well as the larger amount of available target material. (In some cases, the available target material is up to three times larger because of the circumferential design.) As a result, the life of the cylindrical target is often five to 10 times higher than with a planar magnetron.
Optimized SputteringThe rotating cylindrical magnetron provides a valuable alternative to planar magnetrons. Because the target tube rotates over a stationary closed-loop racetrack, the system overcomes most of the shortcomings associated with the typical erosion groove formation in planar magnetrons. Almost complete target consumption can be achieved by optimizing the magnet bar configuration. The system offers a reduced arc rate and better anode functionality in an AC switching mode, and it can also generate higher power densities and sputter yields because the heat load is uniformly spread over the complete target tube surface. Finally, since a tubular target contains about three times more material than a planar target for the same width, the target lifetime or coating volume can be five to 10 times higher compared to planar magnetrons.
With the rotating cylindrical magnetron, high-quality coatings can be applied easily and cost-effectively even in large-area and high-volume applications, giving glass and ceramic manufacturers new options for coating optimization.
References:1. De Bosscher, W.; Gobin, G.; and De Gryse, R., Proc. 3rd Int. Conf. On Coatings on Glass (2000), p. 59.
2. Blondeel, A. and De Bosscher, W., SVC 44rd ATCP (2001), p. 240.