Phase Compensation Circuit for Charged Particle Beam Lens Control
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Solution Overview
Problem
Existing charged particle beam apparatuses face challenges in rapidly switching beam current, half opening angle, and convergence position due to variations in the strength of the electromagnetic lens, leading to prolonged standby times and reduced imaging throughput.
Innovation Solution
Incorporating a phase compensation circuit connected in parallel with the electromagnetic lens to control the lens current, ensuring it monotonically increases or decreases, thereby reducing response delays and ringing, allowing for more precise and rapid adjustments of the beam parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the beam current is increased to improve the S/N ratio, then the S/N ratio is improved, but the aberration in the electron optical system increases and resolution deteriorates
Solution Approach 1:
The patent applies dynamics by making the beam current adjustable and switchable between different magnification conditions. The system dynamically adapts beam current based on magnification level: using larger beam current for low magnification imaging and smaller beam current for high magnification imaging, thereby optimizing both S/N ratio and resolution for different operational states
Solution Approach 2:
The patent changes the beam current parameter according to magnification requirements. By switching beam current between large and small values based on whether low or high magnification imaging is performed, the system resolves the trade-off between S/N ratio and resolution
2Reliability
If the number of frames is increased to improve the S/N ratio through frame addition, then the S/N ratio is improved, but the imaging time increases
Solution Approach 1:
The patent dynamically adjusts the number of frames based on magnification conditions. For low magnification imaging, the system uses a smaller number of frames combined with larger beam current, while for high magnification imaging, it uses appropriate frame numbers with smaller beam current, thereby optimizing both S/N ratio and imaging time for different operational states
Solution Approach 2:
The patent changes the number of frames parameter according to magnification requirements and combines it with beam current adjustment to achieve optimal imaging performance
3Productivity
If the strength of the convergence effect of the electromagnetic lens is switched rapidly to change beam current and half opening angle, then the imaging throughput is improved, but the standby time increases due to response delays and ringing
Solution Approach 1:
The patent applies preliminary action by predicting the variation in the strength of the convergence effect of the electromagnetic lens before switching occurs. The prediction unit forecasts lens strength variation, and the control unit uses this prediction to adjust the lens current in advance, thereby reducing response delays and ringing effects, and shortening standby time for rapid imaging throughput
Solution Approach 2:
The patent implements feedback by using the predicted variation in lens strength to adjust the lens current. The control unit receives prediction information and modifies the lens current accordingly to compensate for anticipated variations, thereby stabilizing the convergence effect and reducing standby time
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 shortens the time for the convergence effect of the electromagnetic lens to stabilize, reduces noise, and enables faster imaging by predicting and controlling the variation in the strength of the convergence effect, thus improving imaging quality and throughput.
Implementation Method 1
an electromagnetic lens; a lens control electric source for controlling strength of a convergence effect of the electromagnetic lens
Implementation Method 2
a phase compensation circuit which is connected to the lens control electric source in parallel with the electromagnetic lens, and controls a lens current at the time of switching the strength of the convergence effect of the electromagnetic lens such that the lens current monotonically increases or monotonically decreases
Data Source
AI summary
A charged particle beam apparatus includes a charged particle beam source which irradiates a sample with a charged particle beam, an electromagnetic lens, a lens control electric source for controlling strength of a convergence effect of the electromagnetic lens; and a phase compensation circuit which is connected to the lens control electric source in parallel with the electromagnetic lens, and controls a lens current at the time of switching the strength of the convergence effect of the electromagnetic lens such that the lens current monotonically increases or monotonically decreases.