Talking About My Work I work in the Center for Advanced Thin Film Technology . My research focuses on the growth of copper films on various substrates such as titanium nitride, tantalum, tantalum nitride, tantalum silicon nitride, and tungsten nitride. In particular, I study the initial stages of film growth, also called nucleation. The purpose of my research is to identify the major mechanisms during nucleation that are responsible for the film structure, stress, and adhesion to the substrate. Control of these film properties is of great interest to semiconductor companies.
Copper is used as wiring in computer chips, and the technology is new.
Previously, aluminum doped with 0.5 weight percent copper was used. Apart from some technical difficulties, copper has the advantage over aluminum that it conducts an electrical current easier, leading to faster chip performance. Copper also shows better resistance to electromigration, which is the deformation of the interconnections by the electrical current. That means that chips with copper interconnections are more reliable than chips with aluminum. The metal-nitride substrates that I mentioned above are used as thin 'barrier layers' to prevent the copper atoms in the 'wiring' to diffuse to other areas in the chip where they could potentially destroy transistors, or electrical insulation.