| US 7,551,273 B2 | ||
| Mask defect inspection apparatus | ||
| Akihiko Sekine, Itabashi-ku (Japan); Ikunao Isomura, Kawasaki (Japan); Toshiyuki Watanabe, Kawasaki (Japan); Shinji Sugihara, Kawasaki (Japan); and Riki Ogawa, Kawasaki (Japan) | ||
| Assigned to Kabushiki Kaisha TOPCON, Tokyo (Japan) | ||
| Filed on Apr. 22, 2008, as Appl. No. 12/81,852. | ||
| Application 12/081852 is a continuation of application No. 11/083202, filed on Mar. 18, 2005, granted, now 7,379,176. | ||
| Claims priority of application No. 2004-081767 (JP), filed on Mar. 22, 2004. | ||
| Prior Publication US 2008/0204723 A1, Aug. 28, 2008 | ||
| Int. Cl. G01N 21/00 (2006.01) | ||
| U.S. Cl. 356—237.5 [356/237.1; 356/237.2; 356/237.4] | 17 Claims |
| 1. A mask defect inspection apparatus, comprising:
an illumination optical system which illuminates a plurality of illumination areas including at least a first illumination
area and a second illumination area different from each other of a mask on which a pattern is formed;
an objective lens facing the mask;
a first focusing lens which receives first illumination light from the first illumination area of the mask obtained through
the objective lens;
a second focusing lens which receives second illumination light from the second illumination area of the mask obtained through
the objective lens;
a first detection sensor which obtains an image of the pattern in the first illumination area of the mask based on the first
illumination light received by the first focusing lens;
a second detection sensor which obtains an image of the pattern in the second illumination area of the mask based on the second
illumination light received by the second focusing lens;
a first moving mechanism which moves the first detection sensor in a direction of an optical axis of the first detection sensor
to change a position of focusing between sites of the pattern in the first illumination area in a film-thickness direction
of the mask and the image of the pattern obtained by the first detection sensor, such that the image of the pattern obtained
by the first detection sensor is changed corresponding to the film-thickness direction of the mask; and
a second moving mechanism which moves the second detection sensor in a direction of an optical axis of the second detection
sensor to change a position of focusing between sites of the pattern in the second illumination area in the film-thickness
direction of the mask and the image of the pattern obtained by the second detection sensor, such that the image of the pattern
obtained by the second detection sensor is changed corresponding to the film-thickness direction of the mask.
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