In this work the stress and grain structure of electrodeposited gold films was determined as a function of time from deposition, with measurements being conducted in time intervals of minutes to days after deposition.
A test structure that allows accurate and unambiguous measurement of out of plane distortion (OPD) was developed. Using this structure the time evolution of the stress of the films was followed using an interferometric microscope. Scanning ion microscopy was used to determine the time evolution of the grain structure of the samples. This technique, based on focused ion beam imaging, allows determination of grain structure of thin films without special sample preparation or restrictions in film thickness.
The sign, magnitude, and stability of the stress at room temperature was found to be a function of the rate of deposition and the concentration of additive in the electrodeposition solution.
For some of the films studied, grain growth from the hundreds of Angstroms to tens of microns was found to occur in a matter of minutes at room temperature.