Optics: measuring and testing – By alignment in lateral direction
Patent
1997-12-05
1999-05-25
Font, Frank G.
Optics: measuring and testing
By alignment in lateral direction
356401, 356373, 356375, G01B 1100
Patent
active
059074051
ABSTRACT:
Alignment is performed with a high degree of accuracy by detecting an offset in the Z position of a wafer mark. A focal position detecting system of a multipoint type is provided which irradiates spot beams on a plurality of measurement points substantially equally distributed on the exposure field of an projection optical system and detects the heights or levels of the irradiated positions. An alignment illumination beam for detecting the position of the wafer mark is irradiated as a slit beam from an alignment sensor, and the spot beams are set so as to be overlaid with the irradiated position of the slit beam. A sample shot where the measured value of a level at the irradiated position of the spot beam exceeds an allowable range of the measured value of a level at another measurement point is excluded from alignment data, and the coordinate positions of each shot area on a wafer are calculated by an EGA method.
Magome Nobutaka
Mizutani Shinji
Font Frank G.
Nikon Corporation
Ratliff Reginald A.
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