摘要:
In one embodiment, a first vacuum chamber of an electron beam column has an opening which is positioned along an optical axis so as to pass a primary electron beam that travels down the column. A source that emits electrons is positioned within the first vacuum chamber. A beam-limiting aperture is configured to pass a limited angular range of the emitted electrons. A magnetic immersion lens is positioned outside of the first vacuum chamber and is configured to immerse the electron source in a magnetic field so as to focus the emitted electrons into the primary electron beam. An objective lens is configured to focus the primary electron beam onto a beam spot on a substrate surface so as to produce scattered electrons from the beam spot. Controllable deflectors are configured to scan the beam spot over an area of the substrate surface. Other features and embodiments are also disclosed.
摘要:
One embodiment relates to an electron-beam apparatus for defect inspection and/or review of substrates or for measuring critical dimensions of features on substrates. The apparatus includes an electron gun and an electron column. The electron gun includes an electron source configured to generate electrons for an electron beam and an adjustable beam-limiting aperture which is configured to select and use one aperture size from a range of aperture sizes. Another embodiment relates to providing an electron beam in an apparatus. Advantageously, the disclosed apparatus and methods reduce spot blur while maintaining a high beam current so as to obtain both high sensitivity and high throughput.