Charged Particle Beam Divider with Segmented Detectors
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Solution Overview
Problem
Existing charged particle beam devices are limited in their ability to analyze secondary electrons effectively, as they often rely on high-pass filters that interfere with primary beams and do not efficiently detect particles of all energies, leading to reduced throughput in specimen inspection, particularly in applications like wafer inspection where image contrast is crucial.
Innovation Solution
A charged particle beam device with a divider that separates the beam into low and high energy components, allowing for angle-sensitive detection by segmented front and reverse detectors, enabling comprehensive analysis of secondary and backscattered particles without energy thresholds, thereby enhancing contrast and throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a high-pass filter grid is used to detect secondary electrons, then high energy electrons can be detected, but the filter interferes with the primary electron beam and low energy electrons cannot be detected
Solution Approach 1:
The detector is divided into multiple segments arranged in different spatial positions and orientations. Each segment detects electrons from specific angular ranges, allowing the system to capture both low and high energy electrons without requiring a single filtering element that would interfere with the primary beam.
Solution Approach 2:
The patent introduces an electrostatic lens system as an intermediary between the specimen and detectors. This lens system focuses and directs electron trajectories without requiring physical filter grids in the detection path, thereby eliminating primary beam interference while enabling energy-selective detection.
2Device complexity
If only high energy secondary electrons are detected, then the detection setup is simpler, but the image contrast and inspection throughput are reduced
Solution Approach 1:
The detector array is segmented into multiple independent detection elements positioned at different angles and distances from the specimen. This segmentation enables simultaneous detection of electrons with different energies and emission angles, improving image contrast and inspection throughput without significantly increasing overall system complexity.
3Device complexity
If a single detector is used to detect all secondary electrons, then the device is simpler, but the ability to distinguish electron energy and angle information is lost
Solution Approach 1:
The detector is divided into multiple segments with distinct spatial positions and orientations. Each segment captures electrons from specific angular ranges and energy levels, allowing the system to preserve both energy and angle information simultaneously while maintaining relatively simple device architecture.
Solution Approach 2:
The patent transitions from a single-point detector to a spatially distributed detector array. By adding spatial dimensionality to the detection system, the patent enables simultaneous measurement of multiple electron beam parameters (energy, angle, position) without requiring complex spectrometers or analyzers.
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 allows for the detection and analysis of particles with arbitrary energies and angles, improving the contrast and throughput of the inspection process, enabling more effective specimen surface inspection without energy threshold limitations.
Implementation Method 1
a divider adapted to divide a beam of charged particles into a low energy beam and a high energy beam
Implementation Method 2
a front detector for detecting the high-energy beam, and at least one reverse detector for detecting the low energy beam, wherein the front detector and/or the at least one reverse detector are segmented
Data Source
AI summary
The present invention relates to an analyzing system with improved detection scheme and a charged particle beam device comprising the same. The analyzing system for analyzing a beam of charged particles has a divider to divide the beam of charged particles according to their energies into a low energy beam and a high energy beam; a front detector for detecting the high energy beam; and at least one reverse detector for detecting the low energy beam. The divider is positioned between the front detector and the at least one reverse detector and the front detector and/or the at least one reverse detector are segmented.