Patent ID: 6396569
Filing Date: 2002-05-28
Classification: G01M,G02B,G03F

Abstract:
A method of measuring aberration of a projection lens in a photolithographic patterning system comprising the steps of:taking a first alignment measurement with a test reticle having a variable linewidth and a variable pitch size on an outer alignment mark; changing the illumination conditions of photolithographic equipment that projects light upon said test reticle; and taking a second alignment measurement with said test reticle having a variable linewidth and a variable pitch size on an outer alignment mark and comparing said second alignment measurement to said first alignment measurement to determine an alignment offset due to said change in illumination; wherein said test reticle comprises the alignment mark including four sets of five by five resin arrays adjacent to two sets of lines having a first pair aligned vertically and a second pair aligned horizontally, wherein the first and the second set of lines are placed adjacent to each other, each of first and second pair of lines facing opposite the other, each set of lines forms a pentad.