Charged Particle Beam Control Using Kikuchi-Line Crystal Alignment
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Solution Overview
Problem
Existing charged particle beam apparatuses face challenges in accurately determining and adjusting the crystal orientation of samples, especially when the external and internal crystal directions differ, leading to difficulties in obtaining high-resolution images due to limitations in diffraction pattern analysis and contamination issues with narrow electron beams.
Innovation Solution
A charged particle beam apparatus that automatically adjusts the crystal orientation by acquiring a diffraction pattern including Kikuchi lines, calculating the crystal zone axis, and controlling the sample stage based on the inclination angle, allowing for precise adjustment without user intervention or prior simulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a narrow primary electron beam is implemented by using an irradiation aperture with a hole diameter of several micrometers, then the diffraction spot becomes thin and spot positions can be separated, but contamination is likely to be attached to the irradiation aperture and replacement frequency increases
Solution Approach 1:
The patent changes the parameter of beam formation from physical aperture restriction to optical lens control. By adjusting the irradiation lens intensity to control beam diameter, the system avoids the contamination issue of physical apertures while maintaining the ability to produce thin diffraction spots for precise spot position separation.
2Length of moving object
If the intensity of the irradiation lens is adjusted to implement a thin primary electron beam, then beam width is controlled, but excitation condition changes and axis adjustment of the electron microscope must be readjusted
Solution Approach 1:
The patent implements automatic axis adjustment using detected diffraction patterns as feedback. The system acquires diffraction patterns, calculates crystal orientation, and automatically adjusts the sample stage inclination angle accordingly, eliminating the need for manual axis readjustment when beam parameters change.
3Ease of operation
If crystal orientation is adjusted under a condition different from observation condition, then adjustment can be performed, but accurate crystal orientation cannot be calculated
Solution Approach 1:
The patent performs preliminary crystal orientation calculation by acquiring diffraction patterns under observation conditions, then uses this information to determine the precise sample stage adjustment needed. This ensures the orientation is calculated and adjusted under the actual observation conditions, guaranteeing accuracy.
4Loss of information
If a diffraction pattern is acquired to calculate crystal orientation, then orientation information can be obtained, but the process requires manual operation and time consumption
Solution Approach 1:
The patent implements automatic crystal orientation determination where the system itself performs diffraction pattern acquisition, analysis, and sample stage adjustment without user intervention. The control unit automatically calculates crystal orientation from detected patterns and controls the sample stage to achieve the correct inclination angle, making the system self-sufficient.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables automatic and accurate adjustment of the crystal orientation, improving image resolution and reducing contamination risks, while accommodating samples with unknown structures and fine features.
Implementation Method 1
acquire a diffraction pattern including a plurality of Kikuchi lines, calculate a crystal zone axis of the sample by performing analysis based on a plurality of intersections at which two Kikuchi lines included in the diffraction pattern intersect with each other
Data Source
AI summary
A charged particle beam apparatus includes: a movement mechanism; a particle source; an optical element; a detector; and a control mechanism, in which the control mechanism acquires a diffraction pattern including a plurality of Kikuchi lines, calculates a crystal zone axis of the sample by performing analysis based on a plurality of intersections at which two Kikuchi lines included in the diffraction pattern intersect with each other, calculates an inclination angle of the sample based on the crystal zone axis and an irradiation direction of the charged particle beam, and controls the moving mechanism based on the inclination angle.