Charged Particle Beam Aperture AC Voltage Alignment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The optimal mounting position of an annular aperture or electrode in charged particle beam apparatuses is difficult to adjust due to the center of the annular aperture not coinciding with the position of the brightest charged particle beam image, unlike circular apertures.
Innovation Solution
A charged particle beam apparatus that includes a charged particle beam aperture with a drive mechanism and power supply capable of applying AC voltage, allowing the aperture position to be adjusted such that the charged particle beam image remains concentric with the AC voltage changes, facilitating precise alignment on the optical axis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If an annular aperture is used to improve depth of focus and obtain spherical aberration correction, then image quality is improved, but the aperture positioning becomes difficult because the center of the annular aperture does not coincide with the brightest beam position
Solution Approach 1:
A circular aperture is introduced as an intermediary component to facilitate the positioning of the annular aperture. The circular aperture is positioned at the brightest beam location, and the annular aperture is positioned relative to it. This intermediary allows indirect positioning of the annular aperture without requiring direct alignment with the brightest beam position, thereby solving the positioning difficulty while maintaining image quality improvements.
2Manufacturing precision
If the center of the annular aperture is disposed on the optical axis, then spherical aberration correction is achieved, but the charged particle beam with highest current density is blocked
Solution Approach 1:
The aperture system is segmented into two distinct components: a circular aperture and an annular aperture. The circular aperture allows the central high-current-density beam to pass through, while the annular aperture provides spherical aberration correction for the peripheral beams. This segmentation enables both functions to coexist without mutual interference, maintaining both beam intensity and aberration correction.
3Ease of operation
If a circular aperture is used, then the aperture can be easily positioned at the brightest beam location, but depth of focus and spherical aberration correction are not improved
Solution Approach 1:
The circular aperture and annular aperture are merged into a single aperture unit that functions as an integrated system. The circular aperture provides easy positioning and allows central beam passage, while the annular aperture叠加 on top provides depth of focus improvement and spherical aberration correction. The combination of both aperture types in one unit delivers both ease of operation and enhanced image quality.
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 easy and appropriate positioning of annular apertures on the optical axis, improving usability and adjustment precision in charged particle beam apparatuses.
Implementation Method 1
a charged particle beam aperture power supply that applies a voltage to the charged particle beam aperture... in a state where an AC voltage is applied to the charged particle beam aperture by the charged particle beam aperture power supply
Data Source
AI summary
When a charged particle beam aperture having an annular shape is used, since a charged particle beam directly above the optical axis having the highest current density in the charged particle beam is blocked, it is difficult to dispose the charged particle beam aperture at an optimal mounting position. An charged particle beam apparatus includes a charged particle beam source that generates a charged particle beam, a charged particle beam aperture, a charged particle beam aperture power supply that applies a voltage to the charged particle beam aperture, an objective lens for focusing the charged particle beam on a sample, a detector that detects secondary charged particles emitted by irradiating the sample with the charged particle beam, a computer that forms a charged particle beam image based on the secondary charged particles detected by the detector, in which the position of the charged particle beam aperture is set so that the charged particle beam image does not move and changes concentrically in synchronization with the AC voltage, in a state where an AC voltage is applied to the charged particle beam aperture by the charged particle beam aperture power supply.