An Electron Backscatter Diffraction (EBSD)-Based Automated Tool for Ceramic Capacitor Grain Size Analysis

Ceramic capacitors continue to be recurring problem parts for NASA, despite best
efforts to screen out potential defects and failures through environmental and
electrical testing and nondestructive inspection techniques such as acoustic
microscopy. The physical properties of ceramic capacitors necessitates thin
dielectric layers capable of withstanding significant electric fields. Any defects in
those ceramic layers can result in reduced insulation resistance failure modes
including short circuit failures, so the quality and consistency of the dielectric
material is critical. The size of the individual ceramic grains in the dielectric
material is a critical parameter.

However, judging “grain size” is not so simple—in a single capacitor there can be
wide variation in grain sizes observed. It is theorized that by studying the grain
size distributions of “known good” and “known bad” lots of capacitors, some
conclusions could be drawn that would allow us to better predict to the reliability of
future lots based on grain size distributions. The initial goal of this effort was to
find or develop an automated tool that could inspect a capacitor and return grain
size distribution results.