METHOD OF INSPECTING SHAPE OF SOLDER

摘要

PROBLEM TO BE SOLVED: To provide a method of inspecting the state where a bump of an area-array package is separated from a pattern on a printed board. SOLUTION: In an image obtained by applying an X-ray to a BGA type area-array package mounted on a substrate, cross-sectional areas near the top and middle of a bump are calculated and the ratio of the areas is calculated from the two calculated cross-sectional areas. If the calculated ratio of the areas is larger than a previously set lower limit, soldering is judged to be normal soldering, and if not, soldering is judged to be open soldering.