Electron beam device
View Patent ↗Disclosed here is a high resolution scanning electron microscope having an in-lens type objective lens. The microscope is structured so as to detect transmission electrons scattering at wide angles to observe high contrast STEM images according to each sample and purpose. A dark-field detector is disposed closely to the objective lens magnetic pole. The microscope is provided with means for moving the dark-field detector along a light axis so as to control the scattering angle of each detected dark-field signal.
1. An electron microscope, comprising:
an accelerating electrode for accelerating a primary electron beam emitted from an electron source;
an objective lens for focusing the accelerated primary electron beam on a specimen;
a deflector for two-dimensionally scanning the primary electron beam over the specimen;
a detector for detecting transmitted electrons transmitted through the specimen; and
a display for displaying a specimen image using a signal from the detector, and
wherein the detector is disposed at a position where, among the transmitted electrons transmitted through the specimen, transmitted electrons of a scattering angle of 100 mrad or above are detected when the acceleration voltage of the primary electron beam is 50 kV or below, and
wherein the detector comprises a moving mechanism that is movable in an optical axis direction of the electron microscope.
2. The electron microscope according to claim 1 , wherein the objective lens is an in-lens type objective lens.
3. The electron microscope according to claim 2 , wherein the detector is disposed at a position at which charged particles whose scattering angle is 100 mrad or above are detected and that is below a position at which the transmitted electrons are re-focused.
4. The electron microscope according to claim 1 , wherein the detector is movable in a direction in which the contrast of the specimen image becomes higher.
5. The electron microscope according to claim 1 , wherein the detector is movable in a direction in which the contrast of a specimen image representing a predetermined element among elements constituting the specimen becomes higher.
6. The electron microscope according to claim 1 , further comprising:
an opening in the center of the detector through which the transmitted electrons pass; and
a second detector for detecting the transmitted electrons that have passed through the opening.