公开(公告)号：JP4016472B2

公开(公告)日：2007-12-05

申请号：JP279398

申请日：1998-01-09

Applicant: 株式会社日立製作所

Inventor： 朝宏 久邇 ,  俊二 前田 ,  千絵 宍戸 ,  高志 広井 ,  淳三 東 ,  幸雄 松山 ,  麻紀 田中 ,  裕治 高木

IPC: G01B11/30 ,  G01N21/956 ,  G01B15/04 ,  G01B15/08 ,  G01N21/88 ,  G01N21/93 ,  G01N23/225 ,  G01R31/302 ,  H01J37/22 ,  H01L21/66

Abstract: PROBLEM TO BE SOLVED: To eliminate an erroneous detection by correcting uneven density and distortions of two images containing patterns which should be originally identical and comparing the both to detect and discriminate parts differing from each other as defects. SOLUTION: Images f (x, y) and g (x, y) from an image memory section are inputted by a roughly positioning circuit 21 to be roughly positioned. An uneven density correction circuit 22 receiving the results inputted corrects uneven density values of the patterns which should be originally identical and reduces any uneven density difference existing at parts without defect to such an extent that the difference can be recognized to be normal. Then, to remove effect by unsteady distortions of the images, positional deviations are corrected by a distortion correcting circuit 23 so that any distortion of the images will not be detected and discriminated as defects. The two images subjected to the correction of the distortions further undergoes a highly accurate positioning with a precisely positioning circuit 24. A density circuit 25 performs a comparison processing of the images thus finished with the correction of the uneven density and distortions and the positioning and any different part therebetween is detected and discriminated as defect. This eliminates erroneous detection, thereby enabling highly reliable detection of fine defects.