Case S5: Comparison of tooling for sputtering
In the previous cases we analyzed a planar magnetron cathode coupled with two different fixture rotations: single-axis rotation and planetary rotation. Here we draw some comparison of the two. Taking the absolute thickness values (which are directly proportional to the deposition rates) and material-collection values from the output of V-Grade 5S we can create a comparison table for the two rotation methods, shown below.
With planetary rotation, the deposition rate is less than a third of that of the single-axis rotation (for a target operated under the same condition). In terms of throughput, however, the planetary setup has an edge over the single-axis rotation because of its quadrupled load capacity.
The material collection is, in fact, a reliable measure of throughput. Assuming both systems are fully loaded, the ratio of throughput between the planetary and single-axis is 25/21, not considering the time spent in pumping down. If pump-down is required between loads, the planetary rotation system should gain more in throughput.
In terms of thickness uniformity, the planetary-rotation system yields significantly better intrinsic uniformity. With properly designed and installed correction masks, both systems can produce coatings with uniformity around 0.2% or better.
The planetary-rotation system has another advantage if ultra-thin layers are to be deposited. The higher intrinsic uniformity (and the use of a slimmer mask) means the planetary system is more friendly to the deposition of ultra-thin layers. Please refer to "Get the most out of your coaters" for the drawback of employing correction masks.
These observations are known empirically to engineers. With V-Grade 5S we can gain a more precise knowledge through quantification.
