Need for Standardization of EBSD Measurements for Microstructural Characterization of Thin Film Structures

Microstructural characterization of metal thin films includes measurement of grain size, crystallographic texture and misorientation angle across grain boundaries. All of these measurements can be made simultaneously by the use of electron backscatter diffraction (EBSD) in the scanning electron microscope. The use of EBSD measurements to characterize microstructure requires the collection and analysis of thousands of individual diffraction patterns, and the extraction of statistical quantities of interest from the data set. The results depend on the particular analytical procedures used. Since the grains in interconnect structures are often much smaller than those in bulk materials, the measurement and reporting protocols require adaptation of procedures developed for bulk materials. Here we demonstrate results from a specific procedure for collecting and analyzing EBSD data on electrodeposited copper films. We show that without careful controls, the apparent grain size can vary by a factor of two or more, and the time required to acquire the data can differ by hours. The demonstrated practical advantages of EBSD over previously available techniques and the severe effect of experimental parameters on the results support the need for standardization of the methods used for microstructural characterization by use of EBSD.