Aluminum Spiking Mechanism in Contact Holes Studied by High-Resolution Analytical TEM

Abstract

AbstractAl-spiking in contacts to Si were studied on a microscopic scale by a detailed cross sectional TEM analysis. Electron spectroscopic imaging and energy dispersive x-ray microanalysis with a I nm high-current electron probe formed by a field emission gun helped to identify the Al-diffusion paths and the reaction mechanisms which lead to contact failure. Combinations of advanced PVD-Ti/TiN barrier layers and cold/hot or high-pressure AlSiCu-fills revealed that the highly rugged TiN barrier sidewalls and thick Ti sidewall layers are the weak points which cause Al-spiking.