Molecular Dynamics Simulation of Void Generation during Annealing of Copper Wiring

Abstract

In the production of LSIs, annealing is necessary to coarsen the crystal grains in the wires. In this process, wiring breakdown is frequently caused by defect generation at the T-shaped buried wire. To overcome this difficulty, we investigated the conditions for defect generation and the atomic behavior during the annealing process by molecular dynamics simulation. We focused on the influence of the adhesion strength between substrate and wire materials on void generation. As samples for the simulation, a Cu single crystal was buried in three different substrates, Si, Ti, and W. After structural relaxation at low temperature (50 K), the movements of individual Cu atoms were simulated for different annealing temperatures using the molecular dynamics method. The strain of the buried wire was also varied where the thickness of the covered layer, the width and the height of the wire were fixed. We found that the system with strong adhesion strength between substrate and wire materials suppressed void generation.

The Relationship between Nanocluster Precipitation and Thermal Conductivity in Si/Ge Amorphous Multilayer Films: Effects of Cu Addition

“…In this expression, , , , and are repulsive force, attractive force, coulomb force, and Van der Waals' force, respectively. More information about the extended Tersoff potential may be found in the literature [17].…”