Three-Element Electrostatic Lens for Stable Beam Collimation
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Solution Overview
Problem
Existing charged particle-optical devices face challenges in efficiently collimating primary beams due to sensitivity to vibrations, complexity in manufacturing, and increased aberrations, which affect the accuracy and throughput of defect detection in semiconductor manufacturing processes.
Innovation Solution
An electrostatic lens is introduced comprising an upbeam charged particle-optical element, a macroscopic charged particle-optical element, and a downbeam charged particle-optical element, with defined apertures and potential differences to control beam divergence, reducing sensitivity to vibrations and aberrations, and facilitating easier manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional electrostatic lens design is used to collimate primary beams, then beam collimation is achieved, but the device becomes sensitive to vibrations and manufacturing complexity increases
Solution Approach 1:
The electrostatic lens is divided into three separate charged particle-optical elements (upbeam, macroscopic, and downbeam elements) with distinct functions. Each element has specific aperture configurations that work together to achieve beam collimation while reducing overall system complexity and vibration sensitivity through functional distribution.
Solution Approach 2:
The patent introduces a macroscopic charged particle-optical element that operates at a different scale than the upbeam and downbeam elements. This macroscopic element provides overall beam control while the smaller elements handle fine adjustments, creating a multi-scale system that reduces sensitivity to vibrations and simplifies manufacturing.
2Ease of operation
If conventional electrostatic lens designs are used, then beam divergence control is achieved, but aberrations in the primary beams increase
Solution Approach 1:
Each charged particle-optical element has locally optimized aperture configurations tailored to its specific function. The upbeam element has apertures optimized for initial beam shaping, the macroscopic element has apertures for intermediate control, and the downbeam element has apertures for final collimation. This local optimization minimizes aberrations at each stage of beam processing.
Solution Approach 2:
The upbeam element performs preliminary beam shaping and conditioning before the beams reach the macroscopic element. This preliminary action prepares the beams for subsequent collimation while minimizing the introduction of aberrations that would require correction later in the system.
3Reliability
If complex electrostatic lens systems are used to reduce vibration sensitivity, then vibration sensitivity decreases, but manufacturing difficulty increases
Solution Approach 1:
By segmenting the lens into three independent elements, each element can be manufactured separately using standardized processes and then assembled. This segmentation reduces the manufacturing complexity of individual components while achieving the vibration sensitivity reduction benefits of a multi-element design.
Solution Approach 2:
The patent employs charged particle-optical elements with apertures that can be dynamically adjusted or configured to optimize performance under different conditions. This dynamic capability allows the system to maintain low vibration sensitivity through active control rather than requiring overly complex rigid structures that would be difficult to manufacture.
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 electrostatic lens enhances beam collimation, reduces sensitivity to vibrations, and simplifies manufacturing, thereby improving the accuracy and throughput of defect detection in semiconductor manufacturing processes.
Implementation Method 1
applying a potential difference between an upbeam charged particle-optical element, of the electrostatic lens, in which are defined a plurality of upbeam apertures for respective beams of the plurality of beams and a macroscopic charged particle-optical element, of the electrostatic lens, in which is defined a macroscopic aperture for the plurality of beams
Data Source
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AI summary
An electrostatic lens for a charged particle-optical device comprises: an upbeam charged particle-optical element in which are defined a plurality of upbeam apertures for respective beams of a plurality of beams of charged particles; a macroscopic charged particle-optical element in which is defined a macroscopic aperture for the plurality of beams; and a downbeam charged particle-optical element in which are defined a plurality of downbeam apertures for respective beams of the plurality of beams; wherein the macroscopic charged particle-optical element is located between the upbeam charged particle-optical element and the downbeam charged particle-optical element.