Original Publication Date: 1984-Nov-01
Included in the Prior Art Database: 2005-Feb-05
This article describes an alignment target of minimal complexity for use by both human operators and automated alignment equipment in which the range of aligner is extended beyond the field of view and target recognition is unaffected by orientation and permits explicit calculation of movement required to achieve alignment. The target shown in Fig. 1, processed onto the wafer, is viewed through a hole in the opaque mask. This hole should be large enough for a human operator to see the center portion of the target. Patterns currently in use suggest a diameter of approximately 1.0 mm. for the mask hole and 0.3 mm. for the central target element. The central target element 10 is surrounded by a pattern of satellite elements 11, placed so that in alignment they are not visible through the mask hole.