Aperture-Array Corrector for Multi-Beam Aberration Tuning
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Solution Overview
Problem
Existing charged particle beam systems face challenges in controlling aberrations effectively, particularly when multiple beams are used, as hardcoded corrections are not optimal in all situations and can be complex to implement, leading to reduced yield and throughput in semiconductor manufacturing.
Innovation Solution
A charged particle-optical device with a lens array and a corrector comprising aperture arrays that apply corrections through adjustable potential differences between facing aperture surfaces, allowing independent control of aberration corrections without altering focusing, enabling adjustment of beam current and landing energy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hardcoded corrections are used in aperture arrays, then aberration correction is provided, but flexibility and adaptability are reduced
Solution Approach 1:
The patent applies dynamics by making the aperture arrays adjustable through voltage control. The aperture patterns can be dynamically changed by applying different voltages to the facing aperture surfaces, allowing the system to adapt correction parameters in real-time based on operating conditions such as beam energy and current, thus resolving the contradiction between providing reliable correction and maintaining flexibility.
Solution Approach 2:
The patent changes physical parameters by allowing voltage to be applied between facing aperture surfaces to modify the aperture patterns. This enables continuous adjustment of correction parameters (such as aperture size, shape, or position) without changing the physical structure, providing both reliable correction and adaptability to different operating conditions.
2Adaptability or versatility
If individual beam voltage control is implemented, then correction flexibility is improved, but device complexity increases
Solution Approach 1:
The patent merges multiple control functions into a unified voltage control system. By applying voltages to facing aperture surfaces that define multiple aperture arrays simultaneously, the system can control multiple correction parameters through a single or limited number of voltage inputs, reducing operational complexity while maintaining flexibility.
Solution Approach 2:
The facing aperture surfaces serve multiple functions: they define aperture patterns for aberration correction, control beam focusing, and enable dynamic adjustment of correction parameters. This multi-functionality reduces the need for separate control mechanisms, thereby reducing device complexity while maintaining high adaptability.
3Adaptability or versatility
If aperture patterns are made adjustable, then adaptability is improved, but control complexity increases
Solution Approach 1:
The patent replaces mechanical adjustment mechanisms with electrical voltage control. Instead of physically moving or changing aperture structures, the system uses electric fields generated by applied voltages to dynamically modify aperture patterns, simplifying control while enhancing adaptability.
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 enhances the flexibility and effectiveness of aberration correction, improving yield and throughput by allowing independent adjustment of beam properties, thus optimizing resolution and beam current across varying operating conditions.
Implementation Method 1
a voltage supply configured to apply a potential difference between the or each pair of facing aperture surfaces to cause the respective species of correction to be applied to the beams of the beam grid
Data Source
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AI summary
The disclosure relates to apparatus and methods for projecting a plurality of charged particle beams towards a sample, and particularly for projecting the beams with reduced aberrations. In one arrangement, a charged particle-optical device comprises a lens array configured to focus a plurality of beams in a beam grid towards a sample position. A corrector comprises at least two aperture arrays having aperture patterns, including one or more pairs of facing aperture surfaces. Each pair corresponds to a species of correction for a respective aberration of the beam grid. A voltage supply is configured to apply a potential difference between the or each pair of facing aperture surfaces to cause the respective species of correction to be applied, the applied potential difference selectable to define a magnitude of the respective species of correction substantially independently of focusing of the beam grid at a sample position.