Sample Holder Orientation Control for Tomography Alignment

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Solution Overview

Problem

Charged particle microscope samples thinner than 300 nm are fragile and prone to misalignment during handling and transfer, leading to rotation misalignments and gamma tilt issues, which affect tomography and image acquisition by reducing accessible areas and causing shadowing and loss of resolution.

Innovation Solution

A sample holder with a defined Z-axis and gamma rotation capability is used to maintain the sample's orientation during focused ion beam milling and transfer, ensuring correct alignment with the charged particle microscope's tilt axis, utilizing orientation elements to fix the sample holder's position within the microscope's cartridge or stage holder.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the sample is mounted on a thin round foil grid for handling and transfer, then the sample can be manipulated and transported, but the sample becomes prone to rotation misalignments and gamma tilt issues during transfer

Engineering Contradiction:

Improvehandling and transportVSAvoidalignment precision

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

The patent introduces an intermediary structure (the sample holder with positioning features) between the grid and the cartridge/stage holder. This intermediary includes positioning features such as notches, protrusions, or keyed interfaces that ensure proper orientation during transfer, thereby maintaining alignment precision while still enabling easy handling and transport through the grid mounting system

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If the sample is thinned to less than 300 nm for charged particle microscopy, then the electron beam can penetrate the sample, but the sample becomes too fragile to be manipulated directly

Engineering Contradiction:

Improvemicroscopy resolutionVSAvoidmechanical strength

Core Design Contradiction:

Measurement precisionVSStrength

Solution Approach 1:

The patent employs a nested structure where the fragile thinned sample is mounted on a grid, which is then mounted on a sample holder, which in turn is placed in a cartridge or stage holder. This nested arrangement provides multiple levels of support and protection, allowing the extremely thin sample to be manipulated and transferred without direct handling, thus preserving both the required thinness for microscopy and the mechanical integrity during handling

Inventive Principle:

Principle #7Nested doll (Nesting)

3Ease of operation

If manual handling steps are used to transfer the grid, then flexibility in operation is maintained, but rotation misalignments occur during transfer

Engineering Contradiction:

Improveoperational flexibilityVSAvoidorientation accuracy

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

The sample holder acts as an intermediary device that combines manual handling flexibility with automated positioning precision. It includes features such as orientation markers, keyed interfaces, or registration features that guide the grid into the correct orientation during transfer, ensuring accurate alignment while still allowing operators to handle the system manually with flexibility

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces purely manual mechanical handling with a hybrid system that incorporates mechanical positioning features (such as tapered interfaces, spring-loaded clamps, or magnetic alignment) into the sample holder and cartridge assembly. These features automatically correct orientation during insertion, reducing reliance on manual alignment skills while maintaining operational flexibility

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 method and sample holder design maintain the sample's orientation consistency from preparation to analysis, reducing misalignment and shadowing, enhancing resolution and accessibility during tomography and image acquisition.

Implementation Method 1

use is made of a focused ion beam for ion milling the sample down to the desired thickness

Methodology Applied

Scientific EffectIon milling: Ion Beam

Implementation Method 2

a parallel, high-energy beam of electrons with an energy of, for example, 300 keV is shot at the sample. As a result of interaction between the electrons and the sample, electrons in the beam will, for example, be deflected, loose energy or be absorbed

Methodology Applied

Scientific EffectElectron beam interaction: Electron Beam