Charged Particle Beam Timing for Fast Electrical Characterization
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Solution Overview
Problem
Existing methods for estimating electrical characteristics of a sample, including capacitance and resistance, are limited by the need for information on temporal changes in charge amount, which can be lengthy for high-resistance samples, and light irradiation can disrupt this process by making changes too rapid for accurate imaging.
Innovation Solution
A charged particle beam apparatus that combines pulsed charged particle beams with controlled light irradiation to set optimal conditions for detecting secondary charged particles, using computation to adjust electron beam and light settings for accurate and rapid estimation of electrical characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the sample is irradiated with light to reduce resistance value, then imaging time can be shortened, but the charge amount changes too rapidly making it impossible to grasp the temporal change
Solution Approach 1:
The patent applies periodic action by using pulsed electron beam irradiation combined with periodic light irradiation. The electron beam is irradiated in pulses at specific intervals, and light is irradiated periodically to control the resistance value. This periodic pulsing allows the system to capture temporal changes at multiple time points (during pulse and between pulses) without requiring continuous observation, thus shortening imaging time while maintaining measurement precision.
Solution Approach 2:
The patent implements dynamics by making the light irradiation condition adjustable and adaptive. The computation device determines optimal light irradiation conditions based on detected secondary charged particle signals. The system dynamically adjusts the timing and intensity of light irradiation to match the charging characteristics of the sample, allowing the light irradiation period to be optimized for each measurement scenario. This dynamic adjustment enables rapid charge amount changes to be captured accurately while maintaining short imaging time.
2Measurement precision
If the electron beam pulse interval time is increased to capture temporal changes, then measurement accuracy improves, but imaging time increases
Solution Approach 1:
The system uses periodic electron beam pulsing with optimized interval times. Instead of using a fixed long interval, the electron beam is pulsed at multiple intervals (during pulse and between pulses), and light irradiation is synchronized to enhance the signal at these periodic moments. This allows temporal changes to be captured at multiple time points within a compressed timeframe, improving measurement precision without proportionally increasing imaging time.
Solution Approach 2:
The patent introduces light irradiation as an intermediary to enhance the detection of temporal changes. By irradiating light during or between electron beam pulses, the resistance value is controlled to produce stronger or more distinguishable secondary charged particle signals. This intermediary light irradiation amplifies the temporal change signals, allowing shorter electron beam pulse intervals to be used while maintaining measurement accuracy.
3Measurement precision
If multiple light irradiation conditions are tested to find optimal settings, then measurement accuracy improves, but the number of required measurements increases
Solution Approach 1:
The patent implements feedback by using the detected secondary charged particle signals to determine optimal light irradiation conditions. The computation device analyzes the signals obtained under different light irradiation conditions and electron beam pulse conditions, then determines the optimal combination. This feedback mechanism allows the system to efficiently identify the best measurement conditions without requiring exhaustive testing of all possible parameter combinations, thus improving measurement precision while maintaining productivity.
Solution Approach 2:
The system efficiently explores parameter changes by systematically varying light irradiation conditions (intensity, timing, duration) and electron beam pulse conditions (interval time, duty cycle). The computation device evaluates these parameter changes and identifies optimal settings based on the detected signals. By using computation to guide parameter optimization rather than random or exhaustive searching, the system achieves high measurement precision with a reasonable number of measurements.
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
Enables rapid estimation of electrical characteristics, including capacitance and resistance, by optimizing electron beam and light conditions to manage sample charging dynamics effectively.
Implementation Method 1
a detector configured to detect a secondary charged particle emitted by irradiating the sample with the pulsed charged particle beam
Implementation Method 2
as disclosed in PTL 4, if the resistance value can be reduced by irradiating the sample with light such as ultraviolet rays
Data Source
AI summary
Charged particle beam apparatus includes: a charged particle optical system to irradiate a sample with a pulsed charged particle beam; an optical system to irradiate the sample with light; a detector configured to detect a secondary charged particle emitted by irradiating the sample with the pulsed charged particle beam; a control unit configured to control the charged particle optical system to irradiate the sample with the pulsed charged particle beam under a predetermined electron beam pulse condition, and control the optical system to irradiate the sample with the light under a predetermined light irradiation condition; and a computation device configured to set the predetermined light irradiation condition based on a difference between a secondary charged particle signal amount detected under a first electron beam pulse condition and a secondary charged particle signal amount detected under a second electron beam pulse condition different from the first electron beam pulse condition.