Evaluation of the residual stress distribution in thin films by means of the ion beam layer removal method

A microelectronic device, designed from multiple structured thin films of different materials deposited on each other, can have a very complex shape. Such a structure can show relatively high residual stresses, which lead to malfunctions and a decrease in lifetime of the device. In this paper a numerical method relying on an inverse optimization algorithm and a finite element (FE) simulation for calculating these stresses is introduced. The evaluation of the residual stress distribution makes use of the so-called ion beam layer removal (ILR) method, where layers of material are removed from a specific region of a micro-cantilever. As a result it is shown that a thin film of material, deposited on a substrate, is occupied by evolving residual stresses through the layer thickness. The calculations and analysis are done automatically using an in-house developed graphical user interface (GUI).