Charged Particle Microscope Transfer Optics for Lorentz Mode

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Solution Overview

Problem

Current microscope systems face challenges in optimizing performance across multiple modes of operation, as improvements in one mode often compromise performance in another, particularly in standard and Lorentz modes, due to limitations in aberration correction and lens configurations.

Innovation Solution

Incorporating a second transfer lens between the corrector and the first transfer lens in charged particle microscopes, allowing for optimized performance in both standard and Lorentz modes by tuning C5 aberration and defocus, while minimizing the impact on C s and C 7 aberrations, and providing additional flexibility in aberration correction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a single transfer lens configuration is used, then the microscope can operate in standard mode, but performance in Lorentz mode is compromised due to inability to optimally tune C5 aberration and defocus

Engineering Contradiction:
Improveperformance in Lorentz modeVSAvoidlens configuration complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The single transfer lens is divided into two separate transfer lenses (first transfer lens and second transfer lens) positioned at different locations in the optical path. This segmentation allows each lens to be independently optimized for different aberration corrections, enabling the system to achieve optimal performance in both standard mode and Lorentz mode without compromising either mode.

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If microscope components are improved to increase performance in one mode, then resolution and magnification improve in that mode, but performance in the other mode deteriorates

Engineering Contradiction:
Improveresolution in standard modeVSAvoidperformance in Lorentz mode
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The dual transfer lens configuration creates a universal optical system that can optimally function in both standard mode and Lorentz mode. The first transfer lens handles aberration correction for standard mode operation, while the second transfer lens provides additional degrees of freedom for optimizing Lorentz mode performance, including tuning C5 aberration and defocus. This multi-functional design allows the microscope to maintain high resolution and performance across different operating modes without compromise.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Manufacturing precision

If aberration correction is optimized for standard mode, then C s and C 7 aberrations are minimized, but C5 aberration and defocus cannot be optimally tuned for Lorentz mode

Engineering Contradiction:
Improveaberration correction in standard modeVSAvoidaberration tuning flexibility
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The system employs dynamically adjustable transfer lenses that can be independently controlled to adapt to different operating modes. The first transfer lens maintains optimal aberration correction for standard mode, while the second transfer lens provides dynamic tuning capability for C5 aberration and defocus in Lorentz mode. This dynamic configuration allows the system to switch between modes and optimize performance for each mode independently.

Inventive Principle:
Principle #15Dynamics

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 configuration enables charged particle microscopes to maintain optimal performance in both standard and Lorentz modes, reducing higher-order aberrations and thermal magnetic field noise, and allowing for optimal performance across a range of accelerating voltages, thereby enhancing resolution and imaging capabilities.

Implementation Method 1

a corrector for correcting axial aberrations

Methodology Applied
Scientific EffectElectromagnetic field interaction: Electromagnetic Induction

Implementation Method 2

a Lorentz lens located between the corrector and the sample holder

Methodology Applied
Scientific EffectLorentz force: Lorentz Force

Implementation Method 3

an objective lens between the Lorentz lens and the sample holder

Methodology Applied
Scientific EffectElectromagnetic lensing: Electromagnetic Induction

Implementation Method 4

a first transfer lens positioned between the corrector and the Lorentz lens, and a second transfer lens positioned between the corrector and the first transfer lens

Methodology Applied
Scientific EffectElectromagnetic lensing: Electromagnetic Induction

Data Source

PatentEP3770946A1Corrector transfer optics for lorentz em
Publication Date: 2021.01.27 FEI CO
  • EP3770946A1 patent drawingFigure 1
  • EP3770946A1 patent drawingFigure 2
  • EP3770946A1 patent drawingFigure 3

AI summary

Charged particle microscopes having an optimized performance across multiple modes of operation are disclosed herein. More specifically, the disclosure includes improved charged particle microscopes that increase and/or optimize the performance of the microscope in both a standard mode of operation and a Lorentz mode of operation. The charged particle microscopes include an extra transfer lens between a corrector and the traditional transfer lens which allows for the flexibility to optimize performance in both the standard mode of operation and the Lorentz mode of operation. For example, in a Lorentz mode of operation, improved charged particle microscope according to the present disclosure can be used to tune the C5 aberration, while hardly affecting defocus and/or Cs aberrations. Additionally, the inclusion of the extra transfer lens provides the charged particle microscopes disclosed herein with an extra degree of freedom with which to zero defocus and total Cs and C5.