Processing, Structure, Properties, and Reliability of Metals for Microsystems

Abstract

Research on the processing, structure, properties and reliability of metal films and metallic microdevice elements is reviewed. Recent research has demonstrated that inelastic deformation mechanisms of metallic films and microelements are a function of temperature, encapsulation, and dimension. Reduced dimension can lead to strengthening or softening, depending on the temperature and strain rate. These results will help in the analysis and prediction of the stress state of films and microelements as a function of their thermal history. Experimental characterization and modeling of stress evolution during film formation has also been undertaken. New microelectromechanical devices have been developed for in situ measurements of stress during processing, and experiments relating stress and structure evolution are underway for electrodeposition and reactive film formation as well as vapor deposition. Experiments relating current-induced stress evolution (electromigration) to the reliability of Cu based interconnects are also being carried out.