Effect of substrate rotation and offset on film thickness uniformity in concave-target magnetron sputtering

Abstract

Thickness uniformity represents a critical quality metric for film deposition, in which controlling wafer-scale non-uniformity is a fundamental but vital requirement for advanced semiconductor manufacturing. Prior studies have demonstrated that concave target configurations can effectively mitigate the “edge phenomenon”, thereby improving thickness uniformity in magnetron-sputtered films. Extending the concave target design, this study develops a thickness distribution model that incorporates substrate-target offset, rotation speed, and deposition time. As the offset increases, the film thickness non-uniformity follows a V-shaped trend, firstly decreases and then increases. With increases in rotation speed and deposition time, the thickness non-uniformity exhibits an oscillatory attenuation behavior. Through three-dimensional two-parameter simulations, the optimal process conditions are identified as an offset of 42 mm, with the rotation speed synchronized to the deposition cycle. These findings offer a theoretical reference for preparing wafer-scale uniform films and are expected to be applicable across a variety of materials.