Design and analysis of a scanning magnetron for uniform planar sputtering onto rectangular substrates

This work presents a novel scanning magnetron for physical vapor deposition that uses planar rectangular targets. It adapts the high-utilization principle of rotary targets (>70%) to a rectangular configuration to improve erosion uniformity and utilization. An innovative magnetron design features inner and outer magnetic poles that form linear and semicircular sections, along with a middle magnetic pole positioned in the gap between them. The middle pole has opposite magnetic polarities oriented parallel to the target surface, matching the polarity of the adjacent inner and outer poles. A driving mechanism scans the magnetron reciprocally along two orthogonal axes: one perpendicular and one parallel to the linear axis of the magnetron. The optimal scan distances are defined as L1 ≥ d along the first direction, which is perpendicular to the linear axis of the magnetron and 0.5d ≤ L2 ≤ 2d along the second, where d is the distance between gap centerlines. The magnetron design in combination with dual-direction scanning achieved 50%–55% target utilization, which is a significant improvement over the typical 30%–40% rates previously reported. The gain results from improved erosion uniformity enabled by the new magnetron and scanning method. To improve full-face erosion at the target edges and corners and enhance particle performance, the semicircular section of the magnetron aligns concentrically with the rounded corner of the rectangular target when the magnetron sweeps beyond the target edge to a limit position. This extends erosion to the edges. Full-face erosion improves target utilization.