SCANNING ELECTRON BEAM DEVICE AND DIMENSION MEASUREMENT METHOD USING SAME

摘要

A scanning electron beam device having: a deflector (5) for deflecting an electron beam (17) emitted from an electron source (1); an objective lens (7) for causing the electron beam to converge; a retarding electrode; a stage (9) for placing a wafer (16); and a controller (15); wherein the stage can be raised and lowered. In the low acceleration voltage region, the controller performs rough adjustment and fine adjustment of the focus in relation to the variation in the height of the wafer using electromagnetic focusing performed through excitation current adjustment of the objective lens. In the high acceleration voltage region, the controller performs rough adjustment of the focus in relation to the variation in the height of the wafer by mechanical focusing performed through raising and lowering of the stage, and performs fine adjustment by electrostatic focusing performed through adjustment of the retarding voltage. It thereby becomes possible to provide a scanning electron beam device that measures, in a highly accurate manner, both the upper part and the bottom part of a groove or a hole having a high aspect ratio.

主权项

1. A scanning electron beam device that comprises an electron source, a deflector for deflecting an electron beam emitted from the electron source, an objective lens for converging the electron beam, a retarding electrode, a stage on which a wafer is loaded, and a controller, and that acquires a SEM image of the wafer by radiating the electron beam onto the wafer and detecting secondary electrons generated from the wafer,
wherein the stage or the objective lens can be raised/lowered; and the controller performs rough focus adjustment responding to a variation in height of the wafer, through mechanical focusing that is performed by raising/lowering the stage or the objective lens.