High-density radio-frequency magnetized plasma sputtering source with rotational square-shaped arrangement of rod magnets for uniform target utilization

Abstract We have developed a high-density radio frequency (RF) magnetized sputtering plasma source with a rotational square-shaped magnet arrangement for uniform target utilization. Eight neodymium rod magnets of 30 × 5 × 3 mm, where the connection between N-pole and S-pole magnets is one side of the square, are mounted on a circular iron yoke disc and an iron cover of 5 × 3 × 1 mm is also used for magnetic shielding of otiose magnetic fields from the permanent magnets. The magnetic field simulation, the measurement of the target erosion and the time-averaged ion flux to the target have been investigated (a) without iron cover and no air gap between N-pole and S-pole magnets, (b) with iron cover and no air gap, and (c) with iron cover and 5 mm air gap, respectively. It is found that the iron covers suppress the horizontal magnetic flux density and the copper target utilization percentage increases from 74.15% to 87.49%. Moreover, by decreasing the air gap between the shielded magnets, the copper target utilization percentage rises from 83.85% to 87.49%. The target utilization as well as the time-averaged ion flux to the target is optimum for case (b).