Method for inspecting an electronic state of a surface of a semiconductor substrate and an apparatus therefor

摘要

Applying a first light ( lambda =950 nm) to a Si wafer to generate electron-hole pairs, a microwave is emitted to the Si wafer and the amount of reflection of the microwave is measured. In like manner, applying a second light ( lambda =633 nm), the amount of reflection of the microwave is measured. The two amounts are normalized by intensities of the lights respectively. In order to cancel an error resulting from geometrical position between a measuring apparatus and the Si wafer, a normalized finite difference is calculated through subtraction between the normalized amounts. The difference may be obtained by another calculation so that it stays in a specified width when a uniformly doped Si wafer is measured.