Stress evolution on tungsten thin-film of an open through silicon via technology

Abstract

We have studied the stress evolution in the tungsten film of a particular open TSV technology during the thermal processing cycle. The film is attached to the via's wall and some plasticity is expected in the metal due to the temperature variation. Our work introduces a stress model for thin-films utilizing the traditional mechanical FEM approach. The results reveal potential reliability issues and a specific evolution of the stress in the tungsten layer.