Numerical analysis of thickness uniformity of thin film deposited by rectangular planar target

Abstract

Due to their great application prospect in large area film deposition, reactangular magnetron sputtering systems with parallel coaxial substrate and rotational axial offset substrate have been established, respectively. The magnetic field distribution on the target surface was incorporated into the existing mathematical model, based on which the finite element method (FEM) was first employed to calculate the film thickness distribution and exhibits excellent adaptability to target-substrate configurations. As the results, for rectangular sputtering system with stationary coaxial substrate, with increasing target-substrate distance, in deposited film, the region with the deviation of film thickness less than 5% decreases, which is mainly due to the changes of thickness distribution in the center of deposited film. This sensitiveness of thickness distribution in the center of deposited film to the alteration of target-substrate distance may be attributed to the anisotropy of angular distribution of the sputtered particles. Furthermore, for the rectangular sputtering system with rotational axial offset circular substrate, with setting the target-substrate distances as 40, 60, 80, 100, 120 and 140 mm, the optimal film thickness uniformity can be obtained at axial offset distances of 65, 70, 80, 90, 110, 130 and 150 mm, respectively. Comparing the optimal distribution of film thickness for each target-substrate distance, it can be concluded that the radius of circular region with the deviation of film thickness less than 5% increases as the increase of the target-substrate distance.