Charged Particle Beam Aperture Angle Evaluation Using Standard Sample Feedback
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Solution Overview
Problem
Existing charged particle beam devices, such as scanning electron microscopes, face challenges in accurately setting and evaluating the beam aperture angle, which significantly influences image resolution and length measurement accuracy, especially when dealing with deep groove or deep hole structures.
Innovation Solution
A charged particle beam device that includes multiple lenses, a control device, a detector, and a processor to set the focus at a predetermined sample height, adjust the beam aperture angle, and calculate the aperture angle based on signal waveforms generated by scanning patterns with known taper angles, allowing for precise evaluation and adjustment of the beam aperture angle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the beam aperture angle is adjusted by setting focus at a predetermined height, then the beam aperture angle can be controlled, but the actual beam aperture angle cannot be accurately measured or evaluated
Solution Approach 1:
A standard sample with a known three-dimensional structure (such as a deep groove or deep hole pattern) is introduced as an intermediary object. By scanning this standard sample and comparing the measured profile with the known structure, the actual beam aperture angle can be indirectly determined and evaluated, resolving the difficulty of direct measurement
Solution Approach 2:
The system scans a standard sample with known structure, measures the actual profile, compares it with the ideal profile, and uses the deviation to evaluate and adjust the beam aperture angle. This feedback mechanism enables accurate measurement and control of the beam aperture angle that was previously difficult to obtain
2Quantity of substance
If lens conditions are adjusted to maximize beam current, then the beam intensity is improved, but the beam aperture angle may not be appropriately set
Solution Approach 1:
Before performing actual measurements, the system first scans a standard sample with known three-dimensional structure to evaluate the beam aperture angle. Based on this preliminary evaluation, the lens conditions are adjusted to optimize both beam current and beam aperture angle, ensuring that subsequent measurements are performed with appropriately set parameters
Solution Approach 2:
The system uses feedback from scanning the standard sample to evaluate whether the beam aperture angle is appropriately set. If the measured profile deviates from the known structure, the lens conditions are adjusted accordingly, ensuring that beam current maximization does not compromise beam aperture angle setting
3Productivity
If the beam aperture angle varies among devices, then machine differences occur, but consistent measurement accuracy across devices cannot be achieved
Solution Approach 1:
Each device scans a standard sample with known structure and uses the measured profile to evaluate its actual beam aperture angle. Based on this feedback, each device adjusts its lens conditions to achieve a standardized beam aperture angle, eliminating machine differences and ensuring consistent measurement accuracy across all devices
Solution Approach 2:
The system changes the lens parameters (excitation currents, focus positions) based on the evaluated beam aperture angle to standardize the measurement conditions across different devices. This parameter adjustment ensures that all devices operate with consistent beam aperture angles, achieving uniform measurement accuracy
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 configuration enables accurate evaluation and setting of the beam aperture angle, reducing machine differences among devices and improving measurement accuracy for deep groove or deep hole structures by minimizing variations in the beam aperture angle.
Implementation Method 1
A charged particle beam device such as a scanning electron microscope irradiates a sample with a finely focused beam
Implementation Method 2
a charged particle beam device including a plurality of lenses, a control device configured to control the plurality of lenses so as to set a focus at a predetermined height of a sample and adjust a beam aperture angle
Data Source
AI summary
An object of the present disclosure is to propose a charged particle beam device capable of appropriately evaluating and setting a beam aperture angle. As one aspect for achieving the above-described object, provided is a charged particle beam device which includes a plurality of lenses and controls the plurality of lenses so as to set a focus at a predetermined height of a sample and to adjust the beam aperture angle. The charged particle beam device generates a first signal waveform based on a detection signal obtained by scanning with the beam in a state where the focus is set at a first height that is a bottom portion of a pattern formed on the sample, calculates a feature amount of a signal waveform on a bottom edge of the pattern based on the first signal waveform, and calculates the beam aperture angle based on the calculated feature amount.