A dual magnetron for plasma sputtering including a source magnetron and an auxiliary magnetron, each of which rotate about the center of the target at respective radii. The positions of the magnetron can be moved in complementary radial directions between sputter deposition and target cleaning. The magnetrons have different characteristics of size, strength, and imbalance. The source magnetron is smaller, stronger, and unbalanced source magnetron and is positioned near the edge of the wafer in sputter deposition and etching. The auxiliary magnetron is larger, weak, and more balanced and used for cleaning the center of the target and guiding sputter ions from the source magnetron in sputter deposition. Each magnetron may have its plasma shorted out in its radially outer position.