Focused Ion Beam Voltage Coordination for Trajectory Control
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Solution Overview
Problem
Focused ion beam apparatuses face challenges in maintaining beam trajectory control when acceleration voltage and beam booster voltage are changed, leading to issues with beam blur, astigmatism, and insufficient deflection, particularly due to the cylindrical shape of the beam booster tube and floating power supplies of electrodes.
Innovation Solution
A focused ion beam apparatus with an ion source, electrostatic lenses, and electrodes in the beam booster tube, where a processing unit adjusts voltages based on measurement conditions to ensure precise beam trajectory control, including alignment, astigmatism correction, and blanking, by calculating the sum of acceleration and beam booster voltages to set optimal voltages for electrodes and lenses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the acceleration voltage of the focused ion beam is reduced, then the damage layer on the sample is reduced, but chromatic aberration increases and beam blur expands
Solution Approach 1:
The patent changes the operational parameters of electrostatic lenses (voltage values) based on the beam booster voltage to maintain optimal beam focusing. When the beam booster voltage is adjusted, the control unit automatically adjusts the voltages of the condenser lens and objective lens to compensate for parameter changes, thereby maintaining beam concentration despite the reduced acceleration voltage.
Solution Approach 2:
The system implements a feedback control mechanism where the control unit monitors the beam booster voltage and automatically adjusts the lens voltages in response. This closed-loop control ensures that chromatic aberration and beam blur are compensated for in real-time, maintaining measurement precision while operating at reduced acceleration voltages to minimize sample damage.
2Use of energy by moving object
If the beam booster voltage is changed, then the ion beam energy is adjusted, but the trajectory control of the ion beam becomes insufficient
Solution Approach 1:
The patent dynamically adjusts multiple voltage parameters (beam booster voltage, condenser lens voltage, objective lens voltage) in a coordinated manner. When the beam booster voltage is changed to adjust ion beam energy, the control unit simultaneously modifies the lens voltages to maintain proper trajectory control, ensuring both energy adjustment and reliable beam guidance.
Solution Approach 2:
The system employs dynamic voltage adjustment where the operational parameters of the electrostatic lenses are made variable in response to beam booster voltage changes. This dynamic adaptation allows the system to maintain optimal trajectory control across different beam energy levels, preventing trajectory control insufficiency when energy is adjusted.
3Ease of operation
If the voltage of electrostatic lenses is not adjusted when beam booster voltage changes, then the system operation is simple, but astigmatism and beam blur increase
Solution Approach 1:
The system implements self-service automatic control where the control unit autonomously adjusts the lens voltages in response to beam booster voltage changes without requiring manual intervention. This automated parameter coordination maintains beam focus quality and minimizes astigmatism while keeping the system easy to operate, as users only need to set the beam booster voltage and the system handles the rest.
Solution Approach 2:
The patent employs coordinated parameter changes where the voltages of the condenser lens and objective lens are automatically adjusted in conjunction with the beam booster voltage. This multi-parameter coordination maintains high beam focus quality and reduces astigmatism while preserving ease of operation through automated control.
4Ease of manufacture
If electrodes in the beam booster tube are used for deflection, then beam positioning is achieved, but beam trajectory control becomes insufficient when voltages are not properly coordinated
Solution Approach 1:
The patent implements coordinated voltage adjustment where the deflection electrode voltages are adjusted in conjunction with the beam booster voltage and lens voltages. This coordinated parameter control ensures that beam positioning is achieved while maintaining reliable trajectory control, preventing the insufficiency that would occur with uncoordinated voltage changes.
Solution Approach 2:
The system employs dynamic voltage coordination where all electrode voltages (deflection electrodes and lens voltages) are made variable and are adjusted in a coordinated manner in response to changes in beam booster voltage. This dynamic parameter coordination ensures both beam positioning capability and reliable trajectory control are maintained simultaneously.
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 solution enables precise control of the ion beam trajectory, reducing beam blur and astigmatism, and ensuring accurate deflection, thereby improving the apparatus's performance and functionality.
Implementation Method 1
an electrostatic lens, which is provided between the one or plurality of electrodes and a sample table, and focuses the ion beam applied with a voltage
Implementation Method 2
a beam booster electrode configured to accelerate the ion beam to a higher level
Data Source
AI summary
The focused ion beam apparatus includes: an ion source configured to generate ions; a first electrostatic lens configured to accelerate and focus the ions to form an ion beam; a beam booster electrode configured to accelerate the ion beam to a higher level; one or a plurality of electrodes, which are placed in the beam booster electrode, and are configured to electrostatically deflect the ion beam; a second electrostatic lens, which is provided between the one or plurality of electrodes and a sample table, and is configured to focus the ion beam applied with a voltage; and a processing unit configured to obtain a measurement condition, and set at least one of voltages to be applied to the one or plurality of electrodes or a voltage to be applied to each of the first electrostatic lens and the second electrostatic lens, based on the obtained measurement condition.