Electron beam apparatus

Abstract

The invention is to observe semiconductor wafers with higher resolution at a low acceleration voltage—in particular, achieving such high-resolution observability when a wafer is inclined or tilted at large angles. A composite lens is used which consists essentially of a single-pole or monopole magnetic field type lens and an electrostatic field invasive lens whereas an electrode of the electrostatic field invasive lens which opposes the wafer is made of a magnetic material while letting a high voltage of the negative polarity be applied to this electrode and the wafer. Even when the wafer is tilted, any astigmatism and axis failure will hardly occur.

Dependencies are inferred from the claim text.