Definition of crack

1. 1 : on semiconductor wafers, a cleavage or fracture that extends to the surface and may or may not pass through the entire thickness of the wafer. [ASTM F1241] 2 : of a semiconductor package or solder preform, a cleavage or fracture that extends to the surface. The crack may or may not pass through the entire thickness of the package or preform. [SEMI G61-94] 3 : in flat panel display substrates, a fissure located at the sheet edge or central area . [SEMI D9-94]