Charged-Particle Lens Assembly for Aperture-Specific Aberration Control
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Solution Overview
Problem
Charged particle-optical apparatuses face challenges in maintaining precise control over beam size and shape due to imperfections in electron-optical lenses, leading to defects in semiconductor IC chip manufacturing, which reduces yield and requires improved inspection and measurement techniques.
Innovation Solution
A charged particle-optical device with a lens assembly comprising multiple plates with apertures and a controller for energy value control, along with aberration correction at specific apertures, ensures precise beam manipulation and correction, enhancing manufacturing tolerances and inspection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If electron-optical lenses are used to focus and manipulate the electron beam, then the beam can be directed and shaped for inspection, but lens imperfections cause beam size and shape deviations from intended specifications
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the energy values of charged particles at different plate locations along the beam paths. This energy modulation compensates for lens imperfections and achieves tighter control over beam size and shape, resolving the contradiction between manufacturing precision and lens reliability.
2Manufacturing precision
If a single corrector is used for aberration correction, then the structure is simple, but correction effectiveness is limited and cannot address aperture-specific aberrations
Solution Approach 1:
The patent implements segmentation by dividing the corrector into multiple individual correctors, each assigned to a specific aperture. This allows independent aberration correction at each aperture, significantly improving correction accuracy while managing complexity through modular design.
Solution Approach 2:
The patent applies local quality by providing customized aberration correction for each aperture based on its specific requirements. Each individual corrector is optimized for its local aperture characteristics, enabling precise correction where needed rather than applying a uniform correction approach.
3Manufacturing precision
If all plates along the beam path use the same energy value, then the system is simpler to control, but beam manipulation precision and manufacturing tolerances cannot be optimized
Solution Approach 1:
The patent implements dynamics by enabling variable energy values at different plate locations along the beam paths. This dynamic energy control allows precise manipulation of beam properties at each stage, improving manufacturing precision while the controller manages the complexity of coordinating multiple energy levels.
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 provides tighter control over charged particle beams, improving the accuracy of defect detection and increasing manufacturing tolerances, thereby enhancing the yield and throughput in semiconductor IC chip production.
Implementation Method 1
a charged particle-optical lens assembly configured to manipulate the beams, the lens assembly comprising a plurality of plates each having an array of apertures for passage of beam paths
Implementation Method 2
the lens assembly comprises a corrector comprising a plurality of individual correctors configured to perform aberration correction
Implementation Method 3
a controller configured to control the charged particle-optical device such that in use charged particles of the beams can have different energy values at the different plate locations along the beam paths
Data Source
AI summary
A charged particle device projects charged-particle beams along beampaths towards a sample location. The device comprises: a charged-particle lens assembly for manipulating the beams and a controller. The lens assembly comprises plates each having an aperture array for passage of beampaths. The plates are at different plate locations along the beampaths. The controller controls the charged-particle device such that charged particles of the beams have different energy values at the different plate locations along the beampaths. The lens assembly comprises a corrector comprising an individual correctors configured to perform aberration correction at respective apertures independently of each other. The corrector is associated with the plate at the plate location at which the energy value is smallest, the strength of an electric field adjacent to the plate is greatest and/or a ratio of the energy value to strength of an electric field adjacent to the plate is smallest.