Identifying and compensating for slip-plane dislocations in photolithographic mask alignment

摘要

Techniques for identifying and determining the orientation, magnitude, and direction of slip plane dislocations transecting semiconductor dies are described, whereby a four point alignment pattern is examined for "squareness" and size integrity. Lack of squareness or significant change in apparent size of various aspects of the alignment pattern indicate slip-plane dislocations. The magnitude, orientation and direction of the dislocations are determined geometrically from measurement of the alignment pattern. Various other aspects of the invention are directed to optimal alignment of a photolithographic mask to a die which has experienced a slip-plane dislocation, and to discrimination between slip- plane dislocation and die-site rotation.