Modeling of thermal processes in magnetrons with single hot target and “sandwich-target”

Abstract

The present work studies thermal processes in DC magnetron sputtering units. A unit with a single hot titanium target is used to deposit films of titanium and titanium nitride. Another sputtering unit called “sandwich-target” is used to deposit films of Cr – Ti or CrN – TiN solid solutions. The sandwich-target consists of a cold chromium target and a hot titanium slotted target located on the same axis. Thermal processes are presented in the form of a stationary heat problem with a surface source of constant power using a three-dimensional homogeneous Fourier equation. The tasks in both cases were solved numerically using the Heat Transfer Module of the COMSOL Multiphysics package. In order to set the boundary conditions, 3D models of the sputtering units were developed. The distributions of the heated elements' surface temperatures were determined. The modeling results were compared with the experimental results. The study found that the influence of the thickness and discharge power on the effective surface temperature of hot elements is nonlinear. In the experimental region, it can be adequately described by a second degree polynomial. The problem-solving method and the developed 3D models are universal and, with the necessary adjustment, can be used to study magnetrons with any metal targets.