Liquid Metal Ion Source Alignment via Scintillator Beam Detection

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Solution Overview

Problem

Focused ion beam systems using liquid metal ion sources face challenges in maintaining alignment due to varying emission regions, requiring time-consuming realignment procedures that involve venting the vacuum chamber, leading to contamination and downtime.

Innovation Solution

A charged particle beam alignment apparatus that includes an alignment aperture plate, a secondary emission element, a scintillator element, and a photodetector, allowing for the detection of scintillation light to locate the charged particle beam axis and compensate for source movement without venting the vacuum chamber.

Engineering Contradictions & Design Principles

VSEngineering 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

Engineering Contradiction:

Improvealignment precisionVSAvoidsystem downtime

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent replaces mechanical disassembly-based realignment with an optical detection system. A scintillator screen converts ion beam position into visible light patterns, allowing alignment to be detected and corrected through optical means rather than mechanical disassembly, thus eliminating downtime while maintaining precision

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces a scintillator screen as an intermediary element that converts invisible ion beam position information into visible light signals. This mediator enables non-invasive detection of beam alignment status without requiring access to internal optical components, resolving the contradiction between maintaining precision and avoiding system disassembly

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If realignment is performed by disassembling the FIB optical column, then alignment precision can be restored, but vacuum chamber contamination increases

Engineering Contradiction:

Improvealignment precisionVSAvoidvacuum chamber contamination

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent replaces mechanical disassembly with optical detection using a scintillator screen. This substitution allows alignment verification and adjustment without opening the vacuum chamber, thereby preventing contamination while maintaining the ability to achieve precise alignment

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The alignment system enables self-diagnosis and self-adjustment capabilities within the sealed vacuum environment. The scintillator screen provides continuous feedback on beam position, allowing the system to maintain alignment without external intervention or chamber opening, thus preventing contamination

Inventive Principle:

Principle #25Self-service

3Quantity of substance

If liquid metal ion source emission region varies in time, then beam current can be maintained, but alignment stability deteriorates

Engineering Contradiction:

Improvebeam currentVSAvoidalignment stability

Core Design Contradiction:

Quantity of substanceVSStability of the object's composition

Solution Approach 1:

The patent implements a feedback mechanism where the scintillator screen continuously monitors ion beam position and provides visual feedback. This allows operators to detect and correct alignment drift caused by emission region variations, maintaining both beam current and alignment stability through active monitoring and adjustment

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent acknowledges the dynamic nature of the liquid metal ion source emission region and provides a dynamic solution through continuous visual monitoring. The scintillator screen enables real-time detection of position changes, allowing the system to adapt to temporal variations while maintaining stable alignment

Inventive Principle:

Principle #15Dynamics

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 beam sources within focused ion beam systems, reducing downtime and contamination risks by allowing alignment procedures to be performed without venting the vacuum chamber.

Implementation Method 1

a scintillator element situated to receive at least a portion of the secondary emission and produce scintillation light in response

Methodology Applied

Scientific EffectScintillation: Scintillation

Implementation Method 2

A photodetector receives the scintillation light produced at the scintillator element

Methodology Applied

Scientific EffectPhotoelectric Effect: Photoelectric Effect

Data Source

PatentUS20250157780A1Methods for determining the virtual source location of a liquid metal ion source

Publication Date: 2025.05.15 FEI CO

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.