Charged Particle Beam Extraction Voltage Control
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Solution Overview
Problem
Charged particle beam apparatuses face difficulties in determining the set value of the extraction voltage due to a low correlation between the angular spread of charged particle beams and the extraction voltage, especially when the diameter of the opening part of the charged particle source is small.
Innovation Solution
A charged particle beam apparatus that includes a gas introduction chamber, a plasma generation chamber, a coil for high-frequency power, an extraction electrode, an ampere meter to measure plasma current, and an extraction voltage calculator to determine the extraction voltage set value based on variations in plasma current with respect to extraction voltage, allowing for precise control of the extraction voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the diameter of the opening part of the charged particle source is made small, then the beam focus is improved, but the correlation between angular spread and extraction voltage becomes low making it difficult to determine the set value
Solution Approach 1:
A current meter is introduced as an intermediary measurement device to indirectly measure the angular spread of the charged particle beam by detecting the current amount that reaches a specific position. This mediator allows measurement of angular spread without directly observing the beam, solving the difficulty caused by the small opening diameter that makes direct measurement hard.
Solution Approach 2:
The patent replaces direct mechanical or optical measurement methods with electrical measurement using a current meter. By substituting the measurement approach from direct physical observation to electrical current detection, the system can accurately determine angular spread even when the opening diameter is small and direct measurement becomes difficult.
2Ease of operation
If traditional methods are used to determine extraction voltage, then the process is simple, but it is time-consuming and wasteful
Solution Approach 1:
The system uses feedback by continuously monitoring the current amount with a current meter and using this information to determine the extraction voltage set value. The feedback loop allows the system to automatically adjust and determine optimal parameters based on real-time measurements, reducing both time and complexity compared to traditional trial-and-error methods.
Solution Approach 2:
The system performs self-determination of the extraction voltage set value by using its own measurement data from the current meter. The charged particle beam apparatus determines its own optimal operating parameters through automated measurement and calculation, eliminating the need for external intervention or time-consuming manual adjustment processes.
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 easy calculation and precise control of the extraction voltage set value, improving the determination of the angular spread of charged particle beams and reducing the need for time-consuming and wasteful methods, even when the opening diameter is small.
Implementation Method 1
a coil wound around an outer circumference of the plasma generation chamber and receiving high-frequency power
Implementation Method 2
an extraction electrode applying an extraction voltage to plasma discharged from a plasma aperture at an outlet of the plasma generation chamber
Implementation Method 3
an ampere meter measuring a magnitude of a plasma current caused by the plasma moved out of the plasma aperture
Data Source
AI summary
An charged particle beam apparatus includes: a gas introduction chamber to which raw gas is introduced; a plasma generation chamber connected to the gas introduction chamber; a coil wound around an outer circumference of the plasma generation chamber and receiving a high-frequency power; an extraction electrode applying an extraction voltage to plasma discharged from a plasma aperture at an outlet of the plasma generation chamber; an ampere meter measuring a magnitude of a plasma current caused by the plasma moved out of the plasma aperture; an extraction voltage calculator calculating, based on variation in the magnitude of the plasma current measured by the ampere meter with respect to variation in the extraction voltage, an extraction voltage set value; and a controller controlling the extraction voltage based on the extraction voltage set value calculated by the extraction voltage calculator.