A system and method for inspecting machine readable marks on one side of a
wafer without requiring transmission of radiant energy from another side
of the wafer and through the wafer. The wafer has articles which may
include die, chip scale packages, circuit patterns and the like. The
marking occurs in a wafer marking system and within a designated region
relative to an article position. The articles have a pattern on a first
side. The method includes the steps of imaging a first side of the wafer,
imaging a second side of the wafer, establishing correspondence between a
portion of first side image and a portion of a second side image, and
superimposing image data from the first and second sides to determine at
least the position of a mark relative to an article.