Chromatic Aberration Corrector for Particle-Optical Apparatus
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Solution Overview
Problem
Current particle-optical apparatus face challenges in correcting chromatic lens errors due to stringent stability demands on power supplies for multipole elements, which are difficult to achieve, especially at high voltages, leading to issues like creep currents and arc-over currents.
Innovation Solution
The apparatus reduces the energy of the beam traversing the corrector to a level lower than that traversing the lens, using transfer optics to adjust the beam energy, thereby relaxing the stability requirements for the corrector's power supplies and minimizing chromatic aberration effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high voltage is applied to the multipole elements for chromatic aberration correction, then correction effectiveness is improved, but power supply stability becomes difficult to maintain due to creep currents and arc-over currents
Solution Approach 1:
The patent changes the voltage parameter by applying different voltages to the first and second sets of multipole elements. The first set operates at a higher voltage for strong correction effect, while the second set operates at a lower voltage for stability. This parameter differentiation resolves the contradiction between correction effectiveness and power supply stability.
Solution Approach 2:
The corrector is segmented into two distinct sets of multipole elements with different voltage requirements. This segmentation allows each set to be optimized independently - one for high-voltage correction and one for stable operation - thereby resolving the contradiction between correction effectiveness and stability.
2Measurement precision
If high voltage is applied to the multipole elements, then chromatic aberration correction is improved, but the corrector design becomes less compact and more complex
Solution Approach 1:
By changing the voltage parameter across different element sets, the patent achieves effective chromatic correction without requiring all elements to operate at high voltage. This reduces the overall complexity and size requirements of the corrector design while maintaining correction effectiveness.
3Measurement precision
If high voltage is applied to the multipole elements, then chromatic aberration correction is improved, but power consumption increases
Solution Approach 1:
The patent applies different voltage parameters to different multipole element sets, with the second set operating at lower voltage. This parameter differentiation reduces overall power consumption compared to operating all elements at high voltage, while maintaining effective chromatic aberration correction through the coordinated action of both sets.
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 results in a more stable and compact corrector design with reduced demands on power supply stability, achieving effective chromatic aberration correction while minimizing undesirable aberrations and power consumption.
Implementation Method 1
The operation of a particle-optical lens relies on the phenomenon that the electrically charged particles are deflected by electric and/or magnetic fields
Implementation Method 2
The operation of a particle-optical lens relies on the phenomenon that the electrically charged particles are deflected by electric and/or magnetic fields
Implementation Method 3
the lens errors of a particle-optical lens can be corrected by subjecting the beam to a plurality of magnetic and/or electric multipole fields, such as dipole fields, quadrupole fields, hextupole fields and octupole fields
Implementation Method 4
the lens errors of a particle-optical lens can be corrected by subjecting the beam to a plurality of magnetic and/or electric multipole fields
Data Source
AI summary
The invention describes a corrector for the correction of chromatic aberrations in a particle lens, such as used in a SEM or a TEM. So as to reduce the stability demands on the power supplies of such a corrector, the energy with which the particle beam passes through the corrector is lower than the energy with which the beam passes through the lens to be corrected.