Dual Deflection System for Particle Beam Aberration Control

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Solution Overview

Problem

Particle beam devices face image errors and aberrations due to the strong off-axis deflection of the particle beam, especially in 'fish-eye' and 'tilt raster' modes, which limit their ability to achieve high spatial resolution and large image fields without significant distortion.

Innovation Solution

A particle beam device with two deflection systems arranged in series, allowing for adjustable angular orientations of their deflection fields to minimize aberrations such as off-axis coma and distortion, enabling optimal performance in various operating modes by adjusting the angular orientation of the deflection fields relative to each other.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single deflection system is used to deflect the particle beam, then the device complexity is reduced, but image errors dependent on deflection angle increase

Engineering Contradiction:
Improvedeflection system configurationVSAvoidimage accuracy
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The deflection system is divided into two separate deflection systems arranged in series. The first deflection system deflects the particle beam by a first angle, and the second deflection system deflects it by a second angle. This segmentation allows independent optimization of each deflection stage to minimize different types of image errors, resolving the contradiction between system simplicity and image accuracy.

Inventive Principle:
Principle #1Segmentation

2Area of stationary object

If the particle beam is strongly deflected off-axis to achieve large image fields, then the area of observable sample increases, but off-axis aberrations increase

Engineering Contradiction:
Improveimage field sizeVSAvoidoff-axis aberrations
Core Design Contradiction:
Area of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The system changes the deflection angles of the two deflection systems as operating parameters. By optimizing the first deflection angle and second deflection angle separately, the system can achieve strong overall deflection for large image fields while minimizing off-axis aberrations through careful parameter selection. This allows the particle beam to traverse larger areas of the sample with reduced distortion.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If the angular orientation of deflection fields is fixed, then the device operation is simplified, but the ability to optimize for different operating modes is reduced

Engineering Contradiction:
Improvedeflection system controlVSAvoidoperating mode flexibility
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The system introduces dynamic adjustability of the angular orientations of the deflection fields. The first angular orientation of the first deflection field and the second angular orientation of the second deflection field can be independently adjusted to optimize performance for different operating modes such as imaging, lithography, or analysis. This dynamic configuration capability enables the system to adapt to various applications while maintaining ease of operation through automated or pre-configured settings.

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 allows for minimized aberrations and optimized beam deflection, enabling high spatial resolution, large image fields, and reduced distortion, even in challenging operating conditions like variable pressure modes, thereby enhancing the device's imaging capabilities.

Implementation Method 1

The particle probe is generally moved by deflecting the particle beam through a magnetic field that is generated with the aid of coils and/or with the aid of an electric field that is generated with the aid of electrodes.

Methodology Applied
Scientific EffectElectric field: Electric Field

Implementation Method 2

The particle probe is generally moved by deflecting the particle beam through a magnetic field that is generated with the aid of coils and/or with the aid of an electric field that is generated with the aid of electrodes.

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Implementation Method 3

The particle probe is generally moved by deflecting the particle beam through a magnetic field that is generated with the aid of coils and/or with the aid of an electric field that is generated with the aid of electrodes.

Methodology Applied
Scientific EffectLorentz force: Lorentz Force

Data Source

PatentEP2461346B1Particle beam apparatus with deflection system
Publication Date: 2018.05.02 CARL ZEISS MICROSCOPY LTD
  • EP2461346B1 patent drawingFigure 1
  • EP2461346B1 patent drawingFigure 2a~2b
  • EP2461346B1 patent drawingFigure 3

AI summary

Two deflection units (9,12) are serially arranged one behind other along optical axis (20), to deflect particle beam in object plane (16). The deflection unit (9) with first and second deflection fields is provided in first operation mode, such that fields with first angular orientation are aligned relative to each other in object plane. The deflection unit (12) with third and fourth deflection fields is provided in second operating mode, such that fields with angular orientation different from first angular orientation are aligned relative to each other in object plane.