The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 25, 1999
Filed:
Dec. 05, 1997
Shinji Mizutani, Kanagawa-ken, JP;
Nobutaka Magome, Kanagawa-ken, JP;
Nikon Corporation, Tokyo, JP;
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.