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Machine translation
1. (WO1997022900) DUAL BEAM AUTOMATIC FOCUS SYSTEM
Latest bibliographic data on file with the International Bureau   

Pub. No.:    WO/1997/022900    International Application No.:    PCT/GB1996/002920
Publication Date: 26.06.1997 International Filing Date: 28.11.1996
Chapter 2 Demand Filed:    02.06.1997    
IPC:
G02B 7/32 (2006.01), G03F 7/20 (2006.01), G03F 9/00 (2006.01), G11B 7/09 (2006.01)
Applicants: BIO-RAD MICROMEASUREMENTS LIMITED [GB/GB]; Haxby Road, York YO3 7SD (GB) (For All Designated States Except US).
SMOUT, Andrew, Michael, Christian [GB/GB]; (GB) (For US Only).
KEENS, Andrew, Peter [GB/GB]; (GB) (For US Only).
HAMMOND, Michael, John [GB/GB]; (GB) (For US Only)
Inventors: SMOUT, Andrew, Michael, Christian; (GB).
KEENS, Andrew, Peter; (GB).
HAMMOND, Michael, John; (GB)
Agent: MARKGRAAF PATENT LIMITED; The Crescent, 54 Blossom Street, York YO2 2AP (GB)
Priority Data:
9525867.9 19.12.1995 GB
Title (EN) DUAL BEAM AUTOMATIC FOCUS SYSTEM
(FR) DISPOSITIF DE MISE AU POINT AUTOMATIQUE A DEUX FAISCEAUX
Abstract: front page image
(EN)The invention relates to a method and means for automatic focusing and has particular use in semiconductor metrology. The invention concerns the use of two beam sources and a single detector. One of said beam sources is projected forwardly of an image plane of an object to be viewed and the second of said beam sources is projected rearwardly of an image plane of an object to be viewed. The reflections from each of said beams are then passed through a vignetting aperture and onto a single focus detector. Using this arrangement it is possible to efficiently and accurately determine the point of focus.
(FR)Cette invention, qui porte sur un dispositif de mise au point automatique à deux faisceaux, a des applications particulières dans le domaine de la métrologie des semi-conducteurs. L'invention porte sur l'utilisation de deux sources de faisceau et d'un seul détecteur. Le faisceau de l'une des sources est projeté en avant d'un plan d'image d'un objet à visionner tandis que celui de la seconde source l'est vers l'arrière d'un plan d'image d'un objet à visionner. Les réflexions provenant de chacun de ces faisceaux traversent une ouverture de vignettisation et passent par un unique détecteur de mise au point. Ce dispositif permet de déterminer le point de mise au point de manière efficace et précise.
Designated States: AL, AM, AT, AU, AZ, BA, BB, BG, BR, BY, CA, CH, CN, CU, CZ, DE, DK, EE, ES, FI, GB, GE, HU, IL, IS, JP, KE, KG, KP, KR, KZ, LC, LK, LR, LS, LT, LU, LV, MD, MG, MK, MN, MW, MX, NO, NZ, PL, PT, RO, RU, SD, SE, SG, SI, SK, TJ, TM, TR, TT, UA, UG, US, UZ, VN.
African Regional Intellectual Property Organization (KE, LS, MW, SD, SZ, UG)
Eurasian Patent Organization (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM)
European Patent Office (AT, BE, CH, DE, DK, ES, FI, FR, GB, GR, IE, IT, LU, MC, NL, PT, SE)
African Intellectual Property Organization (BF, BJ, CF, CG, CI, CM, GA, GN, ML, MR, NE, SN, TD, TG).
Publication Language: English (EN)
Filing Language: English (EN)