Effect of Electromigration on Grooving:

Setup 2: CCT Experiments

The second approach employs free-moving boundary condition (FM-BC) at the cathode edge and reflecting boundary condition (R-BC) for the anode and putting the constant current source (CCS) into the operation from the beginning of the simulation experiments rather then waiting for the end of the complete cathode failure by the shrinkage of the contact area.

Physically this can be realized if the underlayer of high resistance material (Ta, TiN and TiAl3) is acting as a shunt, similar to Blech’s experiments (1975).

This procedure requires modification of the Neuman bounday conditions.

Usual Neumann BC:

he induced (virtual) electric field intensity at the sidewalls counter act against to the normal component of the external field at the boundary.

Modified Neumann BC:

he part of the cathode end bounded by the original sidewalls of the specimen, and the whole anode edge have zero virtual electric field intensity distribution.

figure 7