Methodology for an assessment of the degree of barrier permeability at via bottom during electromigration using dissimilar barrier thickness

摘要

A system and method is disclosed for determining a barrier permeability at a via. A test structure is formed having a test barrier between two conductors. A substantially constant current is conducted through the test structure to measure the lifetime of the test structure. A barrier permeability value is assigned to the test barrier of the test structure based on the measured lifetime. The system also includes a test structure having a first conductor, a second conductor forming an interconnect, a no-flux barrier substantially impermeable to mass flux between the first and second conductor, a third conductor, and a test barrier between the second and third conductor, to be assessed for the barrier permeability value. A current source supplies the current through the test structure. A timer measures the lifetime of the test structure, and a processor determines the value of barrier permeability alpha of the test barrier based on the measured lifetime of the test structure.