Orientation determination of flip-chip Pb-free solder for TEM application

This paper presents a study done on the orientation of C4 solder bumps with respect to bulk silicon (Si) in transmission electron microscopy (TEM). The research found that when a sample comprising both controlled-collapse-chip-connection (C4) solder and Si was oriented with respect to a known zone axis of Si, the orientation of the C4 solder grains were approximately the same, varying by only by a few degrees of tilt, compared to the sample was oriented directly with respect to C4 solder grains. This finding was applied to the characterization of tin-silver-copper (SAC) solders in flip chips.