Combined control of magnetic and electric fields for enhanced plasma uniformity and compressive residual stress in large-area DC magnetron sputtering

This study proposes a strategy to simultaneously improve plasma uniformity and achieve compressive residual stress in a large-area DC magnetron sputtering system through combined magnetic and electric-field control. The approach combines localized magnetic field confinement, achieved by adjusting the target–magnet (TM) distance, with electric-field redistribution using grounded anode rods. A quantitative relationship between ion density and residual stress was established based on experimentally measured stress data and plasma simulations. By locally reducing the TM distance in the central region, magnetic confinement was enhanced, resulting in the conversion of initially tensile stress to compressive stress. In addition, the introduction of grounded anode rods redistributed the electric field, contributing to improved plasma uniformity across the substrate. As a result, a uniform compressive stress distribution was achieved, with the central stress transitioning from tensile (+300 MPa) to compressive (−478 MPa). The proposed strategy enables simultaneous control of plasma distribution and residual stress, providing an effective approach for uniform thin-film deposition in large-area sputtering systems. The proposed approach is particularly relevant for large-area display applications requiring precise control of film properties.