Multi-Aperture Field Curvature Correction for Charged Particle Beamlets
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Solution Overview
Problem
Charged particle beam devices, such as scanning electron microscopes, face challenges in achieving high throughput and reducing aberrations, particularly field curvature, when operating in multiple working modes.
Innovation Solution
A charged particle beam device is designed with a beam source, an aperture device creating multiple beamlets, and a field curvature corrector. The field curvature corrector includes multi-aperture electrodes with adjustable electrical potentials to compensate for field curvature in different working modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple beamlets are used to increase throughput, then productivity is improved, but field curvature aberration worsens
Solution Approach 1:
The patent divides the single electron beam into multiple beamlets using an aperture device with multiple openings. Each beamlet can be independently focused and controlled, allowing parallel processing of different regions of the specimen, thereby increasing throughput while enabling individual aberration correction for each beamlet
Solution Approach 2:
The patent applies different focusing conditions and correction parameters to different beamlets based on their specific positions and aberration characteristics. Each beamlet receives tailored field curvature correction through dedicated corrector electrodes, ensuring optimal image quality for each beam while maintaining high throughput through parallel operation
2Manufacturing precision
If field curvature correction is applied to multiple beamlets, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The patent combines multiple field curvature corrector electrodes into a single integrated corrector structure that can simultaneously correct aberrations for multiple beamlets. The corrector electrodes are positioned and configured to generate electric fields that affect multiple beamlets in parallel, reducing the number of separate correction devices needed while maintaining effective aberration correction across all beamlets
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
The solution enables high throughput and improved inspection accuracy by effectively compensating for field curvature across various working modes, maintaining sharp images and consistent beam performance.
Implementation Method 1
a first multi-aperture electrode with a first plurality of openings for the plurality of beamlets, a second multi-aperture electrode with a second plurality of openings for the plurality of beamlets
Implementation Method 2
The field curvature corrector includes a first multi-aperture electrode with a first plurality of openings providing a varying focal length on the plurality of beamlets
Data Source
Figure 1A~1B
Figure 2~3
Figure 4A~4B
AI summary
A charged particle beam device (100) is described, which includes: a beam source (105) configured to generate a charged particle beam (101) propagating along an optical axis (A); an aperture device (110) with a plurality of apertures configured to create a plurality of beamlets (102) from the charged particle beam; and a field curvature corrector (120). The field curvature corrector (120) includes: a first multi-aperture electrode (121) with a first plurality of openings having diameters that vary as a function of a distance from the optical axis (A); a second multi-aperture electrode (122) with a second plurality of openings; and an adjustment device (132) configured to adjust at least one of a first electrical potential (U1) of the first multi-aperture electrode (121) and a second electrical potential (U2) of the second multi-aperture electrode (122). Further, a field curvature corrector (120) and methods of operating a charged particle beam device are described.