Crystal Texture and Electromigration Damage in Al-Based Interconnect Lines Studied by ACOM with the SEM

Abstract

Electromigration, as one of the main failure mechanisms of VLSI circuits, is of great concern to microelectronics industry. The effects of grain morphology as well as texture can be studied on a mesoscale by Automated Crystal Orientation Mapping (ACOM) in the SEM since it provides a detailed description of the microstructure Textural functions (e g pole figures. ODF MODF), statistical parameters (e.g. grains size distribution) as well as a graphical representation of grain structure (COM) can be extracted from the experimental aggregate function. In polycrystalline (not yet bamboo) structured Al-1%Si-0.5%Cu interconnects the spatial arrangement of grains in the line rather than texture seems to be the dominating effect for electromigration failure.