Open Circuit Ball on TMV

摘要

Figure 1 shows a solder ball on a TMV cavity. This termination was seen after the top component was mechanically removed to examine for open connections. There was evidence of some form of residues on the surface ball. This indicated that either dip flux or flux from the dip paste was present on the top package balls prior to placement and reflow. In this case the flux medium was in contact with both balls but failed to permit the two surfaces to reflow together to form a joint.