Magnetic Field Lens Excitation for Reproducible Electron Orbit Control
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Solution Overview
Problem
Existing charged particle beam devices face challenges in achieving high reproducibility of magnetic field responses and accurate electron orbit control, particularly due to hysteresis issues in magnetic field lenses and magnetic coupling between lenses, which lead to difficulties in control and require significant time for adjustment.
Innovation Solution
The solution involves generating an excitation current for the magnetic field lens by combining a direct current with an alternating current, which improves the reproducibility of the magnetic field response and enables highly accurate electron orbit control in a shorter time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a high-load alternating current is applied to a magnetic field lens to relax hysteresis and improve magnetic field response reproducibility, then measurement accuracy is improved, but time is required before measurement can begin
Solution Approach 1:
The patent applies preliminary action by performing hysteresis relaxation treatment before actual measurement begins. The control unit executes a specific current application sequence (applying current in one direction, then in the opposite direction, then again in the first direction) to stabilize the magnetic field lens characteristics in advance, ensuring that when measurement starts, the magnetic field response is already reproducible and stable.
Solution Approach 2:
The patent employs periodic action through the cyclic application of current in alternating directions to the magnetic field lens. This periodic current application pattern effectively traverses and stabilizes the hysteresis loop, creating a reproducible magnetic field response state that persists during subsequent measurements.
2Measurement precision
If divided lenses are used to correct electron profile and improve measurement accuracy, then blurring is corrected, but control becomes difficult and time is required before measurement
Solution Approach 1:
The patent merges the control of multiple divided lenses into a unified control approach. By treating the group of divided lenses as an integrated system with collective excitation current control, the patent simplifies the control architecture while maintaining the ability to correct electron profile blurring, thereby reducing control difficulty and preparation time.
3Volume of moving object
If lenses are placed close together to save space, then device size is reduced, but magnetic coupling occurs making control difficult and time-consuming
Solution Approach 1:
The patent applies preliminary action by performing magnetic coupling compensation through specific current application sequences before measurement begins. The control unit executes a protocol that applies current to affected lenses in predetermined patterns, stabilizing the magnetically coupled system in advance and enabling accurate control despite the close spacing of lenses.
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
This approach enhances the reproducibility of the magnetic field response and facilitates highly accurate electron orbit control in a charged particle beam device, reducing the time required for measurement and improving overall precision.
Implementation Method 1
a magnetic field lens, generates, by combining a direct current with an alternating current, an excitation current
Implementation Method 2
generates an excitation current of a magnetic field lens by combining a direct current with an alternating current
Data Source
AI summary
The present invention has been made in view of the above problems, and an object thereof is to provide a charged particle beam device capable of improving the reproducibility of the magnetic field response of a magnetic field lens and realizing highly-accurate electron orbit control in a short time. A charged particle beam device according to the present invention generates an excitation current of a magnetic field lens by combining a direct current with an alternating current (see FIG. 6A).