Focused Ion Beam Aperture Life Extension via Voltage Control
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Solution Overview
Problem
Focused ion beam apparatuses face challenges in maintaining aperture service life and preventing contaminant buildup when the column valve is closed, leading to reduced performance and prolonged restart times due to ion beam irradiation and lens aberration issues.
Innovation Solution
Control the extraction voltage applied to the extraction electrode or the control voltage applied to the control electrode to set the emission current to 0 μA, or adjust the voltage applied to the condenser electrode to widen the ion beam diameter, allowing for controlled ion beam emission and preventing contaminants without turning off the high-voltage power supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the column valve is closed to maintain vacuum conditions, then the ion source can be protected from atmospheric pressure, but the ion beam continues to irradiate the aperture causing sputtering and aperture degradation
Solution Approach 1:
The harmful ion beam is extracted or removed from the aperture path by deflecting it toward the sample stage using the beam scanner, separating the ion beam trajectory from the aperture to prevent sputtering while maintaining vacuum conditions
Solution Approach 2:
The beam scanner acts as an intermediary device that redirects the ion beam away from the aperture and toward the sample stage, preventing direct interaction between the ion beam and aperture surfaces that would cause sputtering
2Duration of action of stationary object
If the high-voltage power supply is turned off to stop ion beam emission, then aperture sputtering is prevented, but the apparatus restart time is prolonged
Solution Approach 1:
The harmful effect of ion beam irradiation on the aperture is removed by deflecting the beam away from the aperture using the beam scanner, allowing the high-voltage power supply to remain on without causing aperture degradation
Solution Approach 2:
The beam scanner serves as a mediator that redirects the ion beam path, enabling continuous operation of the ion source while protecting the aperture from sputtering damage
3Productivity
If a larger aperture is used to increase beam current, then throughput is improved, but lens aberration increases causing larger beam spot and reduced processing accuracy
Solution Approach 1:
The beam diameter is made dynamically adjustable through the aperture device, allowing selection of different aperture sizes to match different processing requirements, enabling optimization of both throughput and precision for specific tasks
Solution Approach 2:
The aperture diameter parameter is changed to control beam current and beam spot size, allowing adjustment of beam properties to achieve desired balance between throughput and processing 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 approach prolongs the service life of ion sources and apertures, reduces contaminant buildup, and enables quick restart of the apparatus by allowing controlled ion beam emission and maintaining high vacuum conditions.
Implementation Method 1
control the extraction voltage applied to an extraction electrode or the control voltage applied to a control electrode to set the emission current to 0 μA
Implementation Method 2
the ion beam has a sputtering action. When members constituting the apertures are subjected to sputtering by irradiation of the ion beam, surfaces of the members and sidewalls of openings of the apertures are shaved
Implementation Method 3
adjust the voltage applied to the condenser electrode to widen the ion beam diameter
Data Source
AI summary
It is an object of the present invention to provide a focused ion beam apparatus capable of prolonging a service life of an aperture, preventing contaminants from increasing when a column valve is closed, and being quickly restarted.A high-voltage power supply controller lowers an extraction voltage applied to an extraction electrode or lowers a control voltage applied to a control electrode to set an emission to 0 μA when a column valve is closed. The high-voltage power supply controller returns the extraction voltage applied to the extraction electrode to an original extraction voltage or returns the control voltage applied to the control electrode to an original control voltage when a column valve is opened.