Switchable Multi-Perspective Detector for Charged Particle Inspection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current charged particle beam devices face challenges in achieving high-speed detection and enhanced contrast for topography information, particularly in high-throughput defect inspection and review tools, due to limitations in secondary electron collection and signal beam separation.
Innovation Solution
A secondary charged particle detection device with a detector arrangement featuring at least two detection elements separated by a gap, utilizing particle optics with an aperture plate and concave-shaped aperture openings to separate and focus the signal beam into distinct portions, allowing for high-speed topography measurements and improved contrast.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single detector arrangement is used for secondary electron collection, then the device structure is simple, but the detection speed and topography contrast are insufficient
Solution Approach 1:
The detector arrangement is divided into multiple detection elements (first detection element and second detection element) with separate active detection areas. Each element detects secondary electrons from different angular ranges, enabling simultaneous multi-perspective detection that increases detection speed and provides topography contrast information without requiring sequential scanning
2Loss of information
If all secondary electrons are collected by a single detector, then the collection efficiency is high, but the topography contrast and imaging information are reduced
Solution Approach 1:
The detection system segments secondary electrons based on their emission angles using a multi-aperture plate arrangement. The first aperture plate with first aperture openings directs low-angle secondary electrons to the first detection element, while the second aperture plate with second aperture openings directs high-angle secondary electrons to the second detection element. This angular segmentation preserves topography information while maintaining efficient collection through parallel detection paths
Solution Approach 2:
The system adds angular dimension separation by using multiple aperture plates at different positions and orientations. The first aperture plate is positioned at a first distance from the interaction point, and the second aperture plate is positioned at a second distance, creating spatial separation in the angular domain. This enables simultaneous detection of different electron trajectories without loss of collection efficiency
3Measurement precision
If multiple detection elements are used with separated active areas, then the topography contrast and detection speed improve, but the device complexity increases
Solution Approach 1:
The particle optics system is segmented into multiple aperture plates with specifically designed aperture openings. The first aperture plate has first aperture openings that guide low-angle electrons, while the second aperture plate has second aperture openings for high-angle electrons. This segmentation creates distinct optical paths that simplify the overall system design while achieving precise topography measurement through angularly resolved detection
4Ease of manufacture
If the aperture openings are straight-edged, then the manufacturing is simple, but the beam separation and focusing efficiency are reduced
Solution Approach 1:
The aperture openings in both the first and second aperture plates are designed with curved edges instead of straight edges. The first aperture openings have curved edges that efficiently guide low-angle secondary electrons to the first detection element, while the second aperture openings have curved edges that guide high-angle electrons to the second detection element. This curvature optimization improves beam separation and focusing precision while maintaining manufacturing feasibility
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 efficient separation and focusing of secondary electron beams, enhancing detection speed and contrast, thereby improving the throughput and accuracy of defect inspection and review processes in charged particle beam devices.
Implementation Method 1
a particle optics configured for separating the signal beam into a first portion of the signal beam and into at least one second portion of the signal beam
Implementation Method 2
configured for focusing the first portion of the signal beam and the at least one second portion of the signal beam
Implementation Method 3
a first focusing element for focusing the primary charged particle beam on the specimen
Data Source
Figure 1
Figure 2A~2C
Figure 2D~3B
AI summary
A secondary charged particle detection device for detection of a signal beam is described. The device includes a detector arrangement (220) having at least two detection elements (222) with active detection areas, wherein the active detection areas are separated by a gap (G), a particle optics (200) configured for separating the signal beam into a first portion of the signal beam and into at least one second portion of the signal beam, and configured for focusing the first portion of the signal beam and the at least one second portion of the signal beam. The particle optics includes an aperture plate (201) and at least a first inner aperture openings (202) in the aperture plate, and at least one second radially outer aperture opening (204) in the aperture plate, wherein the first aperture opening has a concave shaped portion, particularly wherein the first aperture opening has a pincushion shape.