Image displacement test reticle for measuring aberration characteristics of projection optics
AssigneeTexas Instruments Incorporated
InventorsSandra S. Zheng, Cindy Pan
Life of this patent
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Abstract
A method for testing the image displacement of a reticle following a change in illumination comprising the steps of taking a first image displacement measurement with a test reticle (110) having a variable linewidth (L) and a variable pitch size (s) on an image displacement mark (30, 40, 50, 60, 70, 80, 90, 100), changing the illumination conditions of the photolithographic equipment and taking a second image displacement measurement with the test reticle (110) to determine an image displacement offset due to changes in illumination, is disclosed.
Claims44
A method of measuring aberration of a projection lens in a photolithographic patterning system comprising the steps of:
- taking a first image displacement measurement with a test reticle having a variable linewidth and a variable pitch size on an outer image displacement mark;
- changing the illumination conditions of photolithographic equipment that projects light upon said test reticle;
- and
- taking a second image displacement measurement with said test reticle having a variable linewidth and a variable pitch size on an outer image displacement mark and comparing said second image displacement measurement to said first image displacement measurement to determine an image displacement offset due to said change in illumination.
A method of measuring aberration of projection optics testing comprising the steps of:
- taking a first image displacement measurement with a test reticle having a variable linewidth and a variable pitch size on an outer image displacement mark and a standard inner box as a measurement reference;
- changing the illumination conditions of photolithographic equipment projected upon said test reticle;
- taking a second image displacement measurement and comparing said second image displacement measurement to said first image displacement measurement to determine an image displacement offset due to said change in illumination;
- and
- adjusting a production reticle position to adjust for misalignment based on the image displacement offset.
A method of measuring characteristics of projection optics comprising the steps of:
- taking a first image displacement measurement with a test reticle having a variable linewidth and a variable pitch size on an outer image displacement mark, and a standard inner box as a measurement reference;
- changing the lens position of said photolithographic equipment that projects light upon said test reticle;
- taking a second image displacement measurement and comparing said second image displacement measurement to said first image displacement measurement to determine an image displacement offset due to said change in illumination;
- and
- determining if said projection optics contains a lens with surface defects.
Dependencies are inferred from the claim text.