| US 7,349,105 B2 | ||
| Method and apparatus for measuring alignment of layers in photolithographic processes | ||
| Martin Weiss, Portland, Oreg. (US) | ||
| Assigned to Intel Corporation, Santa Clara, Calif. (US) | ||
| Filed on Sep. 01, 2004, as Appl. No. 10/932,657. | ||
| Prior Publication US 2006/0044568 A1, Mar. 02, 2006 | ||
| Int. Cl. G01B 11/14 (2006.01); G01B 11/02 (2006.01) | ||
| U.S. Cl. 356—620 [356/401; 356/508] | 18 Claims |
| 1. A method for measuring an overlay between a first reticle and a second reticle comprising:
printing a first pattern of the first reticle onto a substrate;
etching the first pattern into the substrate;
printing a second pattern of the second reticle onto the substrate, wherein the second pattern partially overlaps the first
pattern and the printing the second pattern generates an interference pattern on the substrate;
generating a reference mark adjacent to the interference pattern, wherein generating the reference mark comprises:
printing a third pattern of the first reticle onto the substrate, wherein the third pattern is adjacent to the first pattern;
etching the third pattern into the substrate; and
printing a fourth pattern of the second reticle onto the substrate, wherein the fourth pattern is adjacent to the second pattern,
wherein the fourth pattern partially overlaps the third pattern to generate a second interference pattern; and
measuring a shift in the interference pattern to determine the overlay, wherein measuring the shift in the interference pattern
comprises comparing a first position of a first peak of the interference pattern to a second position of a second peak of
the second interference pattern.
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