CAREER: Microstructure Evolution and Interfacial Reaction Paths in Cu Alloy Thin Films

Rensselaer Polytechnic Institute, Troy NY

Investigators

Abstract

9984478 Ramanath This grant seeks an atomic-level understanding of solute-induced grain size and texture evolution in metal alloy films. A goal is to correlate the effects of microstructure and interface chemistry on film properties. Systematic studies are carried out on two model systems, Cu-Mg and Cu-Al, chosen based on their low and high solid-solubilities, respectively, to reveal the effects of solubility and supersaturation on microstructure and interface chemistry evolution. The specific interrelated goals are: 1) reveal the sequence and kinetics of solute segregation, grain growth, and interfacial reactions during film growth and post-deposition annealing; 2) reveal solute segregation paths (e.g., inter- vs. intra-granular) and surface/interface morphology, structure, and chemistry; 3) understand the influence of precipitate morphology, precipitate-matrix crystallography (e.g. coherency), and interface chemistry on grain size and texture evolution; and 4) understand the effects of texture and solute additions on electromigration, and interface chemistry on oxidation and diffusion barrier properties. The overall thrust of the CAREER educational plan is to develop innovative teaching tools and methods to enable students to acquire top-quality technical knowledge, assimilate the art of learning independently, and prepare them for successful professional careers. The distance-learning Materials Characterization course will be converted into an interactive format and a graduate seminar course and an undergraduate elective on thin film materials and processing will be created as well as computer/video modules related to thin film materials for integration in interactive class sessions of the above courses and outreach activities. %%% The resulting knowledge will enable the tailoring of film properties by atomic-level control of microstructure and interface chemistry through strategic solute additions and annealing. The focus is on copper alloys because of the importance of Cu for interconnect applications in microelectronics. Solute additions to Cu have shown promise for preventing Cu diffusion into silica thereby improving adhesion and electromigration resistance. It is essential to reveal the mechanisms of solute-induced film-property enhancements in Cu films to reproducibly create smaller (faster) and more reliable interconnect structures through alloying. ***