Liquid Metal Ion Source Alignment Using Scintillation Detection
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Solution Overview
Problem
Liquid metal ion sources in focused ion beam systems suffer from misalignment issues due to varying emission regions, requiring time-consuming realignment procedures that involve venting the vacuum chamber and risk contamination.
Innovation Solution
A charged particle beam alignment apparatus with a support member, alignment aperture, secondary emission element, and photodetector system is used to detect scintillation light, allowing for real-time compensation of ion beam source misalignment without venting the vacuum chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If realignment is performed by disassembling the FIB optical column, then alignment precision can be restored, but system downtime increases and contamination risk increases
Solution Approach 1:
The patent replaces mechanical disassembly-based realignment with an optical detection system. A scintillator screen converts ion beam position information into visible light patterns, which are then detected by a camera. This optical substitution eliminates the need for mechanical disassembly while maintaining alignment precision, directly resolving the contradiction between alignment precision and system downtime.
Solution Approach 2:
The patent introduces a scintillator screen as an intermediary element that translates invisible ion beam position data into visible light patterns. This intermediary enables non-invasive detection and adjustment of beam alignment without requiring physical access to internal components, thereby avoiding both time loss and contamination risks while preserving measurement precision.
2Measurement precision
If realignment is performed by disassembling the FIB optical column, then alignment precision can be restored, but contamination risk increases
Solution Approach 1:
By substituting mechanical disassembly with optical detection using a scintillator screen and camera system, the patent eliminates the need to open the vacuum chamber. This prevents external contaminants from entering the vacuum environment while still enabling precise alignment measurements through light-based detection of ion beam position.
Solution Approach 2:
The scintillator screen serves as a vacuum-compatible intermediary that converts ion beam information into optical signals detectable through vacuum windows. This approach maintains the vacuum seal integrity, preventing contamination while enabling precise alignment measurements without requiring chamber opening.
3Ease of operation
If the vacuum chamber is vented for realignment, then alignment can be accessed and adjusted, but vacuum integrity is compromised and requires re-evacuation
Solution Approach 1:
The patent introduces a vacuum-compatible optical detection system using a scintillator screen and external camera. This intermediary system allows alignment observation and adjustment through vacuum windows without breaking the vacuum seal, maintaining both ease of operation and vacuum integrity simultaneously.
Solution Approach 2:
The patent replaces mechanical access methods requiring chamber opening with optical detection through vacuum windows. The scintillator screen converts ion beam position into visible light patterns that can be observed and measured without compromising vacuum integrity, while still providing full alignment accessibility.
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 precise and efficient alignment of ion beams within focused ion beam systems, reducing downtime and contamination risks by maintaining alignment without disrupting the vacuum.
Implementation Method 1
a secondary emission element situated to receive a portion of a charged particle beam (CPB) transmitted by the alignment aperture and operable to produce secondary emission in response
Implementation Method 2
a scintillator element situated to receive at least a portion of the secondary emission and produce scintillation light in response
Implementation Method 3
a photodetector situated to receive the scintillation light produced at the scintillator element
Data Source
Figure 1A~1B
Figure 2
Figure 3
AI summary
Variations in charged-particle-beam (CPB) source location are determined by scanning an alignment aperture that is fixed with respect to a beam defining aperture in a CPB, particularly at edges of a defocused CPB illumination disk. The alignment aperture is operable to transmit a CPB portion to a secondary emission surface that produces secondary emission directed to a scintillator element. Scintillation light produced in response is directed out of a vacuum enclosure associated with the CPB via a light guide to an external photodetection system.