Film thickness distribution control with off‐axis circular magnetron sources onto rotating substrate holders: Comparison of computer simulation with practical results

Abstract

Film thickness distribution control in magnetron sputtering systems is of vital importance to the researcher or process engineer, especially when performing cosputtering of superconducting and alloy films. It is time consuming to find the relative spatial position of sources, substrates, and rotational geometry by experiment to obtain optimum film uniformity. A mathematical computer model for film uniformity is developed to enable rapid prediction of optimum geometries using target erosion data. Aluminum films are deposited by rf magnetron sputtering from 100 and 75 mm diam sources at 5×10−3 mbar in argon onto flat rotating workholders at various source to substrate distances and with varying source offsets from the axis of rotation of the workholder. Film thickness distribution is measured by Talystep. Target erosion profile is measured and this information is used in the computer simulation developed to predict film thickness uniformity. Practical results and theory are in good agreement, demonstrating the usefulness of the computer model. The significance of this technique is that much experimental time can be saved to find the best geometry for optimum film thickness distribution.