Detector Substrate Integration for Multi-Beam Electron Aberration Reduction
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Solution Overview
Problem
Existing multi-beam defect inspection systems face challenges in achieving high throughput and image quality due to aberrations in electron beams and the remote placement of detectors, which limits their scalability and integration with array objective lenses.
Innovation Solution
A detector substrate with an array of apertures and sensor units, each equipped with amplification circuits, is integrated into the objective lens assembly to capture and amplify secondary electrons directly, reducing aberrations and enhancing detection efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If detectors are placed remotely from the sample, then the system has easier integration, but detection efficiency decreases and aberrations increase
Solution Approach 1:
The detector substrate is merged with the objective lens assembly, forming an integrated unit where the detector array is positioned adjacent to the aperture array. This merging eliminates the need for separate detector placement while maintaining precise alignment, thereby improving detection efficiency without compromising integration ease.
Solution Approach 2:
The objective lens assembly serves as an intermediary structure that houses both the aperture array and detector substrate. This intermediary configuration allows the detectors to be positioned close to the sample path while maintaining mechanical stability and ease of integration into the existing system architecture.
2Device complexity
If detectors are placed remotely from the sample, then the system structure is simpler, but image quality deteriorates due to aberrations
Solution Approach 1:
By merging the detector substrate with the objective lens assembly, the system maintains a compact structure while positioning detectors at the optimal location for image quality. The integrated design ensures that detectors are close to the aperture array, minimizing aberrations without significantly increasing overall system complexity.
3Device complexity
If a single beam inspection system is used, then the system is simpler, but throughput is limited
Solution Approach 1:
The inspection system is segmented into multiple independent beam paths, with each beam focused on a different region of the sample through the aperture array. Each sensor unit detects signals from its corresponding beam, enabling parallel inspection of multiple areas simultaneously, thereby increasing throughput while maintaining manageable system complexity.
Solution Approach 2:
The objective lens assembly with aperture array serves multiple functions: it focuses multiple beams simultaneously, maintains precise alignment for each beam, and houses the detector substrate for parallel signal detection. This multi-functionality enables high-throughput inspection without proportionally increasing system complexity.
4Reliability
If detector array is integrated with aperture array, then detection efficiency improves, but manufacturing complexity increases
Solution Approach 1:
The detector substrate is merged with the objective lens assembly in a standardized integrated unit. This merging allows for modular manufacturing where the detector array and aperture array are fabricated together as a single component, improving detection efficiency while managing manufacturing complexity through standardization and modularity.
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 improves detection efficiency and reduces aberrations, enabling higher throughput and better image quality in multi-beam defect inspection systems.
Implementation Method 1
The interactions between the material structure at the probing spot and the landing electrons from the beam of electrons cause electrons to be emitted from the surface, such as secondary electrons
Implementation Method 2
the amplification circuit comprising a Trans Impedance Amplifier and/or an analogue to digital converter
Data Source
AI summary
A detector substrate (or detector array) for use in a charged particle multi-beam assessment tool to detect charged particles from a sample. The detector substrate defines an array of apertures for beam paths of respective charged particle beams of a multi-beam. The detector substrate includes a sensor unit array. A sensor unit of the sensor unit array is adjacent to a corresponding aperture of the aperture array. The sensor unit is configured to capture charged particles from the sample. The detector array may include an amplification circuit associated with each sensor unit in the sensor unit array and proximate to the corresponding aperture in the aperture array. The amplification circuit may include a Trans Impedance Amplifier and/or an analogue to digital converter.