Sample Milling Feedback Control for Slice Thickness

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional methods for imaging and milling samples in charged particle microscopes face challenges such as sample damage, non-reproducible slice thickness, and high demands on precision, leading to unusable results or destruction of critical sample material.

Innovation Solution

A method and apparatus that determine the relative position of the sample with respect to the milling beam, allowing for accurate repositioning to correct for sample drift and ensure reproducible layer removal during milling, using a combination of imaging and milling systems with a milling beam source and an imaging system.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional slice-and-view techniques are used to mill away slices of the sample, then the exposed surface can be imaged, but the milling process damages areas of interest and slice thickness is not reproducible

Engineering Contradiction:

Improveslice thickness consistencyVSAvoidsample damage

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent implements a feedback mechanism where the imaging system continuously monitors the sample position and the milled surface quality. The imaging data is fed back to the control system, which adjusts the milling beam parameters and sample positioning in real-time to maintain consistent slice thickness and avoid damage to areas of interest.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent performs preliminary imaging and positioning adjustments before the milling process begins. The system pre-identifies areas of interest and plans the milling path to avoid these regions, and pre-positioning of the sample is performed to ensure accurate slice thickness from the start of the process.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If manual sample handling is performed during milling, then the sample can be repositioned, but the process is time-consuming and prone to errors affecting reproducibility

Engineering Contradiction:

Improvereproducibility of layer thicknessVSAvoidsample handling time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The system implements self-service automation where the imaging system automatically detects sample drift and triggers repositioning actions without human intervention. The control system autonomously adjusts the sample position based on imaging feedback, eliminating the need for manual handling while maintaining reproducible layer thickness.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent replaces manual mechanical sample handling with an automated positioning system controlled by imaging feedback. The mechanical adjustment of sample position is substituted by an automated stage controller that responds to imaging data, reducing both time and human error.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If the milling beam is used to remove sample layers, then volume analysis can be performed, but sample drift causes variability in slice thickness

Engineering Contradiction:

Improvevolume analysis capabilityVSAvoidslice thickness uniformity

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The imaging system provides continuous feedback on sample position and slice thickness during the volume analysis process. This feedback loop allows real-time correction of sample drift, maintaining uniform slice thickness throughout the extended milling operation required for volume analysis.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system dynamically adjusts milling parameters and sample positioning during the volume analysis process. The milling beam parameters and stage position are continuously optimized based on real-time imaging data, allowing the system to adapt to sample drift and maintain precision throughout the extended analysis.

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

This approach enhances the accuracy and reproducibility of sample milling, reducing sample damage and the variability in slice thickness, thereby improving the reliability of Large Volume Analysis.

Implementation Method 1

milling, using a milling beam from said milling beam source, a sample to remove a layer of the sample

Methodology Applied

Scientific EffectIon beam milling: Ion Beam

Data Source

PatentUS20230162945A1Method Of Imaging And Milling A Sample

Publication Date: 2023.05.25 FEI CO

AI summary

The invention relates to method of milling and imaging a sample. The method comprises the step of providing an imaging system, as well as a milling beam source. The method comprises the steps of milling, using a milling beam from said milling beam source, a sample to remove a layer of the sample; and imaging, using said imaging system, an exposed surface of the sample. As defined herein, the method further comprises the step of determining a relative position of said sample, and using said determined relative position of said sample in said milling step for positioning said sample relative to said milling beam. The relative position of said sample can be a working distance with respect to the imaging system, which can be determined by means of an autofocus procedure.