Integrated Multipole Aberration Corrector for Charged Particle Beam
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Solution Overview
Problem
Current aberration correctors for charged particle beam apparatuses face challenges in achieving high-precision assembly and mass production due to complex configurations and sensitivity to dirt and protrusions, leading to difficulties in maintaining machining accuracy and symmetry, which results in unnecessary parasitic aberrations and performance deterioration.
Innovation Solution
The use of multipole elements integrated with insulating materials, such as ceramic, to form a multistage multipole structure, allowing for precise adjustment of mechanical axes and phases, reducing the number of parts and adjustment locations, and enabling easier fine-tuning of electrode positions and gaps, thereby simplifying assembly and enhancing manufacturing accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multipoles are arranged in a multistage structure to form a multipole field, then spherical aberration and chromatic aberration can be corrected, but the configuration becomes complicated with many parts and adjustment locations
Solution Approach 1:
The patent combines multiple multipoles into a single integrated multipole element, merging several adjustment locations into one. This allows the multipole field to be formed while reducing the number of parts and adjustment locations, thus resolving the contradiction between aberration correction capability and configuration complexity
Solution Approach 2:
The integrated multipole element serves multiple functions simultaneously - it forms the multipole field for aberration correction while also providing mechanical support and alignment references. This multi-functionality reduces the number of separate components needed, addressing the complexity issue while maintaining correction capability
2Reliability
If electromagnetic multipole is used to form multipole field, then chromatic and spherical aberration can be corrected, but each pole needs to be insulated electrically and connected magnetically with yoke, increasing configuration complexity
Solution Approach 1:
The patent merges the insulation and magnetic connection functions into the integrated multipole element structure. The insulating material and magnetic yoke are combined in a single configuration rather than being separate components, reducing the overall complexity while maintaining the necessary electrical insulation and magnetic circuit functionality
Solution Approach 2:
The patent uses composite structures combining insulating materials with magnetic yoke materials in the multipole element. This composite approach allows both electrical insulation and magnetic connectivity to be achieved within a unified structure, reducing the number of separate parts and simplifying the overall configuration
3Manufacturing precision
If high-precision assembly of multipoles is performed to maintain symmetry, then multipole field accuracy is improved, but manufacturing and assembly become more difficult
Solution Approach 1:
The patent incorporates alignment references and positioning features directly into the integrated multipole element during manufacturing. This preliminary action ensures that when the element is assembled, the high-precision alignment is already built-in, making the assembly process easier while maintaining the required symmetry accuracy
Solution Approach 2:
The patent combines the alignment reference features with the functional multipole structure in a single integrated element. This merging eliminates the need for separate alignment components and procedures, making high-precision assembly easier while maintaining manufacturing precision
4Reliability
If multipole surface is exposed to vacuum passage, then multipole field can be generated, but the multipole becomes sensitive to dirt and protrusions on the surface
Solution Approach 1:
The patent introduces an insulating material as an intermediary between the multipole surface and the vacuum passage environment. This intermediary layer protects the multipole surface from direct exposure to contaminants while allowing the multipole field to be generated, thus reducing sensitivity to dirt and protrusions
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 enables the construction of aberration correctors with improved assembly accuracy, reduced parasitic aberrations, and enhanced performance, making them suitable for mass production while maintaining high precision and reducing the risk of magnetic field disorders.
Implementation Method 1
the electrostatic type multipole that is used for electrostatic deflection in the SEM, the electron beam lithography system, etc.
Implementation Method 2
the magnetic field type multi-magnetic pole that is intended to be used in the spherical aberration correctors for TEM and STEM, the EELS apparatus, etc.
Data Source
AI summary
The present invention provides an aberration corrector giving excellent assembly accuracy but having fewer parts and fewer adjustment locations in number. In order to achieve it, a multistage multipole is formed by arranging plural combinations of electrodes around an optical axis using alignment blocks, each combination of electrodes being made by brazing-integrating plural electrodes with a ceramic material interposed therebetween.