A novel six-coil multi-mode magnetic field system: design, spatial distribution and modulation of melt flow and oxygen transport in 300 mm Czochralski silicon growth

300 mm Czochralski (Cz)-grown silicon single crystals have become the dominant substrate material for advanced integrated circuit manufacturing. However, conventional fixed-geometry transverse magnetic field (TMF) and cusp magnetic field (CMF) systems widely used in traditional Cz furnaces cannot switch between operating modes, which limits process flexibility. To address this issue, a multi-mode magnetic field system (MFS) based on six independently controlled coils is proposed to achieve flexible switching between TMF and CMF modes. A hybrid two-dimensional (2D) global / three-dimensional (3D) local model was developed to couple the electromagnetic, flow, thermal, and oxygen transport fields. The model was validated against industrial 300 mm Cz furnace experiments. In TMF mode, adjusting the coil current ratios tailors the spatial magnetic field distribution, enabling precise tuning of oxygen content at the solid-liquid (S-L) interface. In CMF mode, the six-coil MFS (6C-MFS) closely reproduces the field distribution of a conventional CMF; the resulting oxygen content differs by less than 3%. Structural optimization with partial coil overlap further reduces the azimuthal magnetic field fluctuation at the melt edge from 0.006 T to 0.002 T. This work provides a foundation for flexible magnetic field regulation strategies for multi-specification production of large-diameter Cz silicon single crystals.