Tongjai Chookajorn

Effects of side reservoirs on the electromigration lifetime of copper interconnects

A new side reservoir test structure is shown to have improved electromigration reliability over conventional end-of-line reservoir structures. This is believed to be due to the ability of the side reservoir to “trap” migrating pre-existing voids before they reach the cathode end. The ability of the side reservoir to ‘trap’ pre-existing voids is believed to be associated with local differences in back-stresses and with the differing adhesion strength of Cu atoms with the Ta/Cu and SiN-SiCN/Cu interfaces.

Monte Carlo Study of Alloy Structures in Bulk and Nanostructured Systems

A Monte Carlo simulation is used to investigate the structure of binary alloys in bulk and nanostructured systems. The structures simulated under the bulk constraint by prohibiting grain boundary states to appear are in good agreement with microstructures in conventional alloy phase diagrams. Structures obtained without forcing the bulk constraint are found to differ from the bulk configurations and display nanoscale structural features that are accessible with suitable nanostructuring and equilibration. A nanostructure stability map is shown to be a useful tool for determining the alloy structures that may emerge from the Monte Carlo simulation without the bulk constraint.