RETICLE HAVING IMPROVED OVERLAY KEY

摘要

A reticle having an improved overlay key is provided to reduce an error range occurring in a patterning process by reducing the critical dimension of a pattern for forming an overlay key. An overlay key is formed on a scribe line(24) that is a boundary between chips of a wafer(W), having the same critical dimension as the critical dimension of a main pattern formed on the chip. A reference key(31a) has a polygonal region and a plurality of lines in the polygonal region. An assistant key(33a) is formed in the reference key, composed of a polygon that has the same shape as the reference key but is formed of a different size from that of the reference key. The plurality of lines formed in the polygonal region cross the line of the reference key.