# US 7,745,787 B2 · Electron beam device

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- Number: US 7,745,787 B2
- Document ID: US7745787B2
- Status: Granted
- Kind: B2
- Application number: 12/071,152
- Filed: 2008-02-15
- Published: 2008-11-27
- Granted: 2010-06-29
- Earliest claimed: 2003-01-07
- Assignees: Hitachi High-Technologies Corporation
- Inventors: Chisato Kamiya; Masahiro Akatsu; Mitsugu Sato
- Web page: https://patentgrep.com/patent/US7745787B2

## CPC

- H01J 37/28: with scanning beams {(H01J37/268, H01J37/292, H01J37/2955 take precedence)}
- H01J 37/244: Detectors; Associated components or circuits therefor
- H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H)

## Abstract

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.

## Claims

### Claim 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.

### Claim 2 (depends on 1)

The electron microscope according to claim 1, wherein the objective lens is an in-lens type objective lens.

### Claim 3 (depends on 2)

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.

### Claim 4 (depends on 1)

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.

### Claim 5 (depends on 1)

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.

### Claim 6 (depends on 1)

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.