Hitachi, Ltd.

Other

Yoichiro Neo

Mari Nozoe

Hidetoshi Nishiyama

Mitsuo Suga

Electron beam is irradiated to a wafer in the midst of steps at predetermined intervals by a plurality of times under a condition in which a junction becomes rearward bias and a difference in characteristic of a time period of alleviating charge in the rearward bias is monitored. As a result, charge is alleviated at a location where junction leakage is caused in a time period shorter than that of a normal portion and therefore, a potential difference is produced between the normal portion and a failed portion and is observed in a potential contrast image as a difference in brightness. By consecutively repeating operation of acquiring the image, executing an image processing in real time and storing a position and brightness of the failed portion, the automatic inspection of a designated region can be executed. Information of image, brightness and distribution of the failed portion is preserved and outputted automatically after inspection.

Method of inspecting pattern and inspecting instrument

An inspection technique for enabling an inspection on a wafer at an early stage during a wafer process. A wafer in a process is irradiated with an electron beam a plurality of times at predetermined intervals under a condition that a junction is backward biased, and secondary electron signals are monitored, so as to evaluate relax time characteristic of a backward bias potential in a p-n junction. Since the potential in the p-n junction decreases according to the intensity of a backward bias current in intermittent time, a backward bias current can be specified from an intensity signal interrelated with the number of secondary electron signals, that is, a potential contrast image on the basis of image information.

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Kokubunji, Japan

Yoichiro Neo