Alignment apparatus

Details Alignment apparatus Alignment apparatus

1990-04-06

1992-09-29

Willis, Davis L.

Optics: measuring and testing

By alignment in lateral direction

With registration indicia

G01B 1100

Patent

active

051517507

ABSTRACT:
There is disclosed an apparatus for transferring a reticle pattern onto a wafer, in which the reticle and the wafer are mutually aligned by irradiating an alignment mark of the wafer with light beams and detecting the optical information from the mark. Depending on the shape of the wafer mark, suitably selected is a first light beam passing through the center of entrance pupil of an objective optical system, or a pair of second light beams passing through the entrance pupil point-symmetrically with respect to its center. The wafer mark consists of a main mark and an auxiliary mark, and the main mark contains a diffraction grating pattern. The second paired light beams and the main mark are used for determining the positional error within an integral fraction of the pitch of the diffraction grating pattern, and the first light beam and the auxiliary mark are used for determining the positional error of an integral multiple of the pitch of the diffraction grating pattern.

REFERENCES:
patent: 3726595 (1973-04-01), Matsumoto
patent: 4636077 (1987-01-01), Nomura et al.
patent: 4650983 (1987-03-01), Suwa
patent: 4655598 (1987-04-01), Murakami et al.
patent: 4677301 (1987-06-01), Tanimoto et al.
patent: 4710026 (1987-12-01), Magome et al.
patent: 4780617 (1988-10-01), Umatate et al.

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