Maxwell design of the magnetic field in an unbalanced magnetron system for optimization toward sputtering of Al-Si alloy

This study improves the utilization rate of aluminum-silicon (Al-Si) targets by optimizing the magnetic field and the magnetic pole position in a nonequilibrium magnetron sputtering discharge. The etch profile of Al-Si targets is determined by combining sputtering experiments with electromagnetic simulations using Maxwell software, which provides information on the initial magnetic field distribution. The effects of two optimization strategies—adjusting the magnetic pole position and intensity, are compared, with a focus on their impact on the parallel magnetic field component (Bx) at characteristic etching positions. The results indicate that adjusting the central magnetic pole has a limited impact. In contrast, reducing the intensity of the peripheral magnetic pole from 6000 to 4000 Gs markedly improves field uniformity. Compared to 6000 Gs, the adjustment lowered the peak magnetic field in the strongly etched area (near the target edge of the target, 35 and 65 mm) by around 16%–21%. Meanwhile, it raised the magnetic field in the weakly etched area (55 mm) approx. 32%, effectively redistributing the magnetic field lines inward. Analysis of the magnetic field in the depth direction revealed an increase in field strength and gradient in areas that were previously subject to weak etching, which activated sputtering and resulted in a flatter erosion profile to achieve a higher final target utilization. This work provides a valuable theoretical and utilitarian approach to optimizing the design of magnetic field for planar magnetron targets, thereby reducing costs and promoting green manufacturing.