- 专利标题: SEM provided with a secondary electron detector having a central electrode
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申请号: US10024777申请日: 2001-12-20
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公开(公告)号: US06646261B2公开(公告)日: 2003-11-11
- 发明人: Jan Martijn Krans
- 申请人: Jan Martijn Krans
- 优先权: EP00204812 20001222
- 主分类号: H01J3728
- IPC分类号: H01J3728
摘要:
The invention relates to wafer inspection by means of a scanning electron microscope (SEM) column in which the secondary electron detector 22, 24 is positioned centrally above the objective lens of the column. Secondary electrons that leave the central part of the specimen in a direction substantially perpendicular to its surface are inevitably collected in the central part of the detector surface where the bore 36 for the primary beam 6 is situated. Consequently, such electrons do not contribute to the detector signal. In order to avoid such a detrimental loss of signal contribution, it is proposed to provide a central electrode 35 in the central bore 36 such that secondary electrons that approach the bore are driven aside towards the electron-sensitive detector region 48.
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