The Influence of Skin Effect on Via-Vicinity-Interfaces Current Density of Cu Interconnects

Abstract

This paper presents a research on skin effect’s influence on the current density distribution of Cu/barrier layer and Cu/cap layer interfaces of copper interconnects’ via vicinities. A two-level Cu-interconnect structure in different positional relationships with the ground plane is discussed. Through the three-dimensional (3D) finite element simulation of the interconnect structure, the variations of current density on three important surface areas are obtained when skin effect is significant, showing that the current density in the three surface areas near the via has been strongly influenced by current crowding and skin effect. So in many cases the influence of skin effect on via top and via bottom failures of Cu interconnects under high frequencies can not be ignored.