Based on the weak formulation for combined surface diffusion and
evaporation/condensation, we derive the governing equation of the finite-element
induced both by stressmigration and electromigration. The corresponding program
is developed for simulating the evolution of the intragranular microcracks
caused by surface diffusion in copper interconnect lines under a gradient stress
field and an electric field. Unlike previously published works, this paper is
focused on how the interconnect linewidth influences the microcrack evolution.
Numerical analysis results show that there exists a critical value of the linewidth
. When
, the
microcrack will drift along the direction of the electric field by a stable form. When
, it
will split into two small microcracks and the decrease of the linewidth is beneficial for
the microcrack splitting. Besides, the critical linewidth increases with the
increase of the electric field and the aspect ratio, and the critical linewidth first
increases and then decreases with the increase of the stress gradient. That is,
the increase of the electric field and the aspect ratio is beneficial for the
microcrack to split. In addition, all of the critical values of the electric field,
the aspect ratio and the stress gradient decrease with the decrease of the
linewidth. The microcrack has a stronger dependence on the linewidth when
.
State Key Laboratory of Mechanics
and Control of Mechanical Structures
Nanjing University of Aeronautics and Astronautics
29 Yudao Street
Nanjing, 210016
China
State Key Laboratory of Mechanics
and Control of Mechanical Structures
Nanjing University of Aeronautics and Astronautics
29 Yudao Street
Nanjing, 210016
China
State Key Laboratory of Mechanics
and Control of Mechanical Structures
Nanjing University of Aeronautics and Astronautics
29 Yudao Street
Nanjing, 210016
China