Charged Particle Detection Layout for Atom Probe Mass Resolution
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Solution Overview
Problem
Existing atom probe microscopes face challenges in preventing the loss of charged particles during flight and accurately identifying particles with close flight times, which affects detection efficiency and mass resolution.
Innovation Solution
A charged particle detection system is introduced, comprising a capture device to create an electric field cage and widen the local electrode aperture, along with an acceleration system to boost kinetic energy and a flight guide system to alter the particle direction, enhancing detection efficiency and mass resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a traditional atom probe microscope is used, then the device structure is simple, but charged particles are lost during flight and mass resolution is poor
Solution Approach 1:
The detection system is divided into multiple functional segments: a capture device with capture electrodes to collect charged particles, an acceleration system with acceleration electrodes to boost particle kinetic energy, and a flight guide system with guide electrodes to direct particles toward the detector. This segmentation allows each component to optimize its function, improving mass resolution while managing complexity through modular design
Solution Approach 2:
Electric fields are introduced as intermediary mechanisms between the charged particles and the detector. Capture electrodes create electric fields to collect particles, acceleration electrodes create electric fields to increase particle energy, and guide electrodes create electric fields to direct particle trajectories. These electric field intermediaries enable precise control of charged particles, significantly improving mass resolution and detection efficiency
2Productivity
If no particle capture device is used, then the device structure is simple, but detection efficiency is low due to particle loss
Solution Approach 1:
The capture device with capture electrodes is positioned to preliminarily collect charged particles immediately after they are generated from the sample, before they can be lost. This preliminary action of capturing particles ensures high detection efficiency by preventing particle loss during the initial phase of particle flight, while the modular capture device design manages the added complexity
3Measurement precision
If particle kinetic energy is not boosted, then the device structure is simple, but particles with close flight times cannot be accurately identified
Solution Approach 1:
The acceleration system with acceleration electrodes changes the kinetic energy parameter of charged particles by applying electric fields. This parameter change boosts particle velocity and extends flight time differences between particles with close mass values, enabling accurate flight time measurement and identification. The acceleration system manages complexity through controlled electric field application
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 system improves detection efficiency by 60-90% and mass resolution by 15-30%, ensuring accurate elemental mapping of semiconductor samples.
Implementation Method 1
a local electrode configured to produce an attractive electric field and to direct a charged particle from a sample towards an aperture of the local electrode
Implementation Method 2
a particle capture device configured to produce a repulsive electric field around a region between the sample and the local electrode and to repel the removed particle towards the aperture
Implementation Method 3
an acceleration system configured to accelerate the charged particles to a velocity sufficient to prevent loss of the charged particles during flight
Implementation Method 4
a guide system configured to create an electric field and to alter a flight path direction of the charged particles exiting the acceleration system
Implementation Method 5
a position detector configured to detect two-dimensional position coordinates of the removed particle and a flight time of the removed particle
Data Source
AI summary
A semiconductor metrology tool for analyzing a sample is disclosed. The semiconductor metrology tool includes a particle generation system, a local electrode, a particle capture device, a position detector, and a processor. The particle generation system is configured to remove a particle from a sample. The local electrode is configured to produce an attractive electric field and to direct the removed particle towards an aperture of the local electrode. The particle capture device is configured to produce a repulsive electric field around a region between the sample and the local electrode and to repel the removed particle towards the aperture. The position detector is configured to determine two-dimensional position coordinates of the removed particle and a flight time of the removed particle. The processor is configured to identify the removed particle based on the flight time.