SUPERPOSITION ACCURACY MEASUREMENT MARK AND SUPERPOSITION ACCURACY MEASURING METHOD

摘要

PROBLEM TO BE SOLVED: To improve the accuracy in superposition by constituting a lower layer pattern, the first circuit pattern on which to superpose the second circuit pattern, of a plurality of patterns different in width. ;SOLUTION: A lower layer pattern 1 consists of three pieces of patterns 1a, 1b, and 1c different in width, and an upper layer pattern 2 consists of two pieces of patterns 2a and 2b different in width. The positions of four pieces of bar-shaped patterns arranged at several sides of a quadrangle are measured, and then the center position among them is computed. After computation of each center position as to a first pattern and a second pattern, the positional discrepancy x between these is measured, and next a board is rotated by 180°, likewise the positional discrepancy (y) is measured. A z=(x+y)/2 value is computed, and this is made an error TIS measured value by a measuring instrument. Performing TIS measurement to all combinations of the first pattern and the second pattern and the selecting the combination of giving the smallest TIS measured value can minimize the error in measurement of superposition accuracy.;COPYRIGHT: (C)2000,JPO