| abstract |
An electron beam column comprises a thermal field emission electron source (15) to generate an electron beam (112), an electron beam blanker, a beam shaping module (128), and electron beam optics comprising a plurality of electron beam lenses (154, 160). In one version, the optical parameters of the electron beam blanker, beam shaping module, and electron beam optics are set to achieve an acceptance semi-angle β of from about 1/4 to about 3 mrads, where the acceptance semi-angle β is the half the angle subtended by the electron beam at the writing plane. The beam-shaping module can also operate as a single lens using upper and lower projection lenses. A multifunction module for an electron beam column is also described. |