Charged Particle Beam Stage Layout for Composite Optical Navigation
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Solution Overview
Problem
Charged particle beam apparatuses face difficulties in accurately and easily obtaining low-magnification images of samples due to the limited field of view and the need for separate optical navigation systems.
Innovation Solution
A charged particle beam apparatus that includes a charged particle beam optical system, a detector, an imaging device, a rotatable stage, and an image composition unit, which allows for the combination of multiple optical images to generate a composite low-magnification image by moving and rotating the stage, reducing the stage's movement range and eliminating the need for a large vacuum chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the stage rotation center is positioned at the center of the optical imaging device's field of view, then the imaging coverage is maximized, but the stage movement range becomes excessively large requiring a large vacuum chamber
Solution Approach 1:
The patent decouples the rotation center positioning from the imaging center by introducing independent translational stages. Instead of rotating around the imaging center in a 2D plane, the system uses a multi-dimensional stage configuration where the rotation center can be positioned independently from the optical axis, effectively utilizing additional spatial dimensions to resolve the contradiction between imaging coverage and stage movement range
Solution Approach 2:
The patent divides the stage system into multiple independent segments: a rotation stage for angular positioning and translational stages for positional adjustment. This segmentation allows the rotation center to be separated from the imaging center, enabling the rotation stage to have a compact movement range while the translational stages provide the necessary positioning flexibility to maintain full imaging coverage
2Loss of information
If multiple optical images are captured by rotating the stage through large angles, then a complete low-magnification image is obtained, but the stage movement range increases requiring larger vacuum chamber
Solution Approach 1:
The patent employs independent translational stages that operate in linear dimensions to compensate for the limited rotational range. By separating the rotation function from the positioning function, the system can capture complete sample information through coordinated translation and rotation movements within a compact vacuum chamber volume
Solution Approach 2:
The translational stages act as intermediaries between the rotation stage and the optical imaging device. They mediate the positioning requirements by adjusting the sample position relative to the optical axis, enabling full sample coverage to be achieved without requiring the rotation stage to traverse large angular ranges that would demand a large vacuum chamber
Data Source
AI summary
A charged particle beam apparatus includes a charged particle beam optical system that irradiates a sample on a sample stage with a charged particle beam; a detector that detects a signal generated from the sample; a charged particle beam imaging device that acquires an observation image from the signal; an optical imaging device that captures an optical image of the sample; a stage that rotatably holds the sample stage; a stage control device that controls movement and rotation of the stage; and an image composition unit that combines a plurality of optical images. The stage is moved so that the center of an imaging range of the optical imaging device is located at a position different from the rotation center of the stage, and then rotated. A plurality of optical images relating to different positions of the sample by rotation operation are acquired and combined to generate the composite image.