Dual-Threshold Particle Detector for Low-Crosstalk Beam Inspection
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Solution Overview
Problem
Existing charged particle beam inspection tools, particularly multi-beam systems, face limitations in detecting backscatter signal particles due to crosstalk, which hinders effective imaging of structures below the surface and overlay targets, limiting throughput in defect detection.
Innovation Solution
A detector system comprising a semiconductor element and a charge-based element, configured to detect signal particles above and below specific energy thresholds, respectively, is integrated into a charged particle device, allowing simultaneous detection of both types of particles, thereby reducing crosstalk and enhancing throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single detector is used to detect all signal particles, then device complexity is reduced, but measurement precision deteriorates due to inability to distinguish energy thresholds
Solution Approach 1:
The detector is divided into two distinct detector elements: a first detector element for detecting signal particles above a first energy threshold, and a second detector element for detecting signal particles below a second energy threshold. This segmentation allows each element to be optimized for its specific detection range, improving measurement precision while maintaining manageable device complexity through functional division.
2Productivity
If multi-beam system is used to increase inspection throughput, then productivity is improved, but crosstalk between beams increases, reducing measurement precision
Solution Approach 1:
By segmenting the detection function into multiple detector elements with different energy thresholds, the system can process signals from multiple beams simultaneously without crosstalk. Each detector element handles specific energy ranges, allowing multi-beam operation at high throughput while maintaining precise backscatter signal detection through dedicated detection channels.
3Device complexity
If only secondary electrons are detected, then device complexity is reduced, but information completeness deteriorates due to lack of subsurface structure information
Solution Approach 1:
The detector system is designed with multi-functionality to detect both secondary electrons (providing surface information) and backscatter electrons (providing subsurface information) using the same detector assembly. This universal detection capability ensures complete information about both surface and subsurface structures without requiring separate detection systems.
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 simultaneous detection of secondary and backscatter signal particles, providing comprehensive information about surface and subsurface structures, improving defect detection accuracy and increasing inspection throughput.
Implementation Method 1
a semiconductor element configured to detect signal particles above a first energy threshold
Implementation Method 2
a charge-based element configured to detect signal particles below a second energy threshold
Data Source
AI summary
A detector for use in a charged particle device for an assessment tool to detect signal particles from a sample, the detector including a substrate, the substrate including: a semiconductor element configured to detect signal particles above a first energy threshold; and a charge-based element configured to detect signal particles below a second energy threshold.