Method and system to interferometrically detect an alignment...

Details Method and system to interferometrically detect an alignment... Method and system to interferometrically detect an alignment...

2006-08-01

2006-08-01

Toatley, Jr., Gregory J. (Department: 2877)

Optics: measuring and testing

By light interference

For dimensional measurement

Reexamination Certificate

active

07084987

ABSTRACT:
Coherent illumination is used to illuminate a symmetrical alignment mark with an image rotation interferometer producing two images of the alignment mark, rotating the images 1800 with respect to each other, and recombining the images interferometrically. The recombined images interfere constructively or destructively, in an amplitude and or polarization sense depending upon the method of recombination, when the alignment sensor is located at the center of the alignment mark. The rotation interferometer is preferably a solid glass assembly made of a plurality of prisms. A detector extracts the alignment information from the image rotation interferometer. The resulting center of the alignment mark is accurately determined. A relatively large number of different alignment mark patterns may be utilized, as long as the alignment mark patterns exhibit one hundred and eighty degree symmetry. Parallel lines, a grid pattern, or a checkerboard grating may be used. The alignment sensor may be applied to a scanning photolithographic system providing sinusoidal alignment signals. The alignment system is particularly applicable to photolithography as used in semiconductor manufacturing.

REFERENCES:
patent: 3945713 (1976-03-01), Doi et al.
patent: 4335313 (1982-06-01), Kreuzer et al.
patent: 4340305 (1982-07-01), Smith et al.
patent: 4504148 (1985-03-01), Kuroki et al.
patent: 4545683 (1985-10-01), Markle
patent: 4549084 (1985-10-01), Markle
patent: 4578590 (1986-03-01), Wu
patent: 4579453 (1986-04-01), Makita
patent: 4697087 (1987-09-01), Wu
patent: 4758976 (1988-07-01), Cohen
patent: 5157459 (1992-10-01), Oono et al.
patent: 5477057 (1995-12-01), Angeley
patent: 5559601 (1996-09-01), Gallatin et al.
patent: 5767523 (1998-06-01), McCullough
patent: 5943135 (1999-08-01), Mishima
patent: 6034378 (2000-03-01), Shiraishi
patent: 6100980 (2000-08-01), Ichikawa
patent: 6242754 (2001-06-01), Shiraishi
patent: 6628406 (2003-09-01), Kreuzer
patent: 6809827 (2004-10-01), Kreuzer
Partial European Search Report, 5 pages, for European Patent Appl. No. 01109039.6, dated Jul. 11, 2005.
European Search Report, 6 pages, for European Patent Appl. No. 01109039.6, dated Feb. 10, 2006.
De Nicola, S. et al., “Reflective grating interferometer: a folded reversal wave-front interferometer,”Applied Optics, vol. 38, No. 22, pp. 4845-4849 (Aug. 1, 1999).
Omatsu, T. et al., “Time-resolved measurement of spatial coherence of a copper vapor laser beam using a reversal shear interferometer,”Optics Communications, vol. 87, No. 5/6, pp. 278-286 (Feb. 15, 1992).
English Abstract of Japanese Patent Publication No. 03130638, published Jun. 4, 1991, 1 page.

Affiliated with

Also associated with

Rating

Method and system to interferometrically detect an alignment... does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Method and system to interferometrically detect an alignment..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and system to interferometrically detect an alignment... will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3657367