SEM Observation Condition Setting via Pulsed Electron Beam
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Solution Overview
Problem
The existing methods for setting observation conditions in scanning electron microscopes (SEM) are cumbersome, often requiring image acquisition, leading to sample pollution or damage, long setup times, and unstable image quality, especially when observing insulators, high resistors, or insulated floating regions, with image reproducibility and analysis being difficult due to user experience-dependent adjustments.
Innovation Solution
An automated method for setting SEM observation conditions involves irradiating a sample with an intermittent pulsed electron beam to analyze the time change of emission electrons, optimizing parameters like acceleration voltage, focus, and illumination current without image acquisition, allowing for stable and reproducible imaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If image acquisition is performed to set observation condition, then observation condition can be determined, but sample pollution or damage occurs
Solution Approach 1:
The patent applies preliminary action by measuring sample characteristics (conductivity, charge state) before performing full imaging. The system uses preliminary electron beam irradiation to detect sample properties, then sets observation conditions based on these pre-measurements, avoiding the need to acquire images for condition setting and thereby preventing sample damage.
Solution Approach 2:
The patent extracts the essential measurement function from the imaging process. Instead of using full imaging to determine observation conditions, the system extracts and measures only the necessary sample characteristics (conductivity, charge state) separately, then uses these extracted parameters to set optimal observation conditions without performing damaging imaging.
2Measurement precision
If image acquisition is performed to set observation condition, then observation condition can be determined, but setting time becomes long and throughput decreases
Solution Approach 1:
The system performs preliminary measurements of sample characteristics quickly before imaging. By measuring conductivity and charge state in advance using fast electron beam pulses, the system determines observation conditions without time-consuming image acquisition, significantly reducing setup time while maintaining accurate condition setting.
Solution Approach 2:
The patent skips the time-consuming image acquisition step for condition setting. The system rushes through the essential measurement by directly detecting sample characteristics (conductivity, charge state) using brief electron beam irradiation, bypassing the lengthy imaging process that would otherwise be required to determine observation conditions.
3Ease of operation
If initially registered adjustment values are used for adjustment parameters, then setting work is simplified, but image stability deteriorates for insulators and high resistors
Solution Approach 1:
The patent dynamically changes observation parameters (acceleration voltage, illumination current, focus) based on measured sample characteristics. For insulators and high resistors, the system detects their charge state and conductivity, then adjusts parameters specifically for these materials, maintaining both ease of operation through automation and image stability through condition optimization.
Solution Approach 2:
The system implements feedback by measuring sample characteristics (conductivity, charge state) and using this information to automatically adjust observation parameters. This closed-loop approach maintains ease of operation through automation while ensuring image stability by adapting parameters to the actual sample properties rather than using fixed initial values.
4Measurement precision
If adjustment parameters are adjusted sensuously based on user experience, then observation condition can be optimized, but adjustment degree greatly depends on user experience and reproducibility is insufficient
Solution Approach 1:
The system applies self-service by automatically measuring sample characteristics (conductivity, charge state) and determining optimal observation conditions without user intervention. The microscope performs its own characterization and self-optimization, eliminating dependence on user experience while maintaining high measurement precision through objective, data-driven parameter selection.
Solution Approach 2:
The patent replaces the mechanical/sensory adjustment process (user experience-based manual tuning) with an automated electronic measurement and control system. The system uses electron beam-based conductivity and charge state measurements to objectively determine observation parameters, substituting subjective user judgment with automated, reproducible electronic control.
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 approach enables optimized observation conditions that reduce sample damage, shorten setup times, and improve image stability and reproducibility, providing images with enhanced contrast suitable for various sample characteristics.
Implementation Method 1
Electrons (Auger electrons, secondary electrons, reflected electrons, or secondary electrons and reflected electrons) emitted from the sample by the irradiation of the primary electrons are detected by a detector
Data Source
AI summary
An automatic setting method of an observation condition to facilitate analysis of an image and a sample observation method by automatic setting in an observation method of a structure of a sample by the electronic microscope and an electronic microscope having an automatic setting function are provided. The method includes a step of irradiating a fixed position in an observation region with an intermittent pulsed electron beam; a step of detecting a time change of an emission electron from the sample by the intermittent electron beam; and a step of setting the observation condition of the electronic microscope from the time change of the emission electron.