OVERLAY MARK

摘要

PURPOSE: An overlay mark is provided to form an overlay mark for measuring overlay and alignment when performing a lithography process of a semiconductor device. CONSTITUTION: An overlay mark comprises an inner box of a type of box in box and an outer box opposite to the inner box. The overlay mark comprises measuring marks with shapes of L and reverse L of different accumulating levels. The measuring marks are formed with a frame type. The measuring marks comprise a first level mark(11) formed with the shape of reverse L , a second level mark(13) formed with the shape of L. The second level mark forms an outer box of the measuring marks with the type of box in box and forms an inner box at an inner side of the outer box. The inner box is the first level mark.