Correlated SEM-LM Imaging for Beam-Sensitive Sample Inspection
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Solution Overview
Problem
Electron microscopy is limited by imaging artefacts and sample modification due to high current densities, particularly affecting vulnerable materials like organic and inorganic samples, leading to chemical reactions and structural changes.
Innovation Solution
An integrated scanning electron microscope (SEM) and light microscope (LM) system is used to determine the position and settings for imaging vulnerable samples, allowing non-invasive determination of regions of interest and adjusting scan parameters to minimize damage, using a designated focusing area and real-time monitoring with LM to adjust SEM settings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If electron microscopy is used to achieve nanometer-scale spatial resolution, then imaging resolution is improved, but sample damage and imaging artefacts increase due to high current densities
Solution Approach 1:
A light microscope is introduced as an intermediary tool to perform preliminary imaging and region-of-interest identification. The light microscope enables navigation and parameter determination without exposing the sample to damaging electron beam currents, thereby mediating between the need for high-resolution electron microscopy and the need to prevent sample damage
Solution Approach 2:
All preliminary actions including sample localization, region-of-interest determination, and electron microscope parameter optimization are performed using the light microscope before electron beam exposure. This preliminary characterization enables the electron microscope to be configured for direct high-resolution imaging of the specific region without prolonged exposure or extensive beam scanning that would cause damage
2Measurement precision
If high current densities are used in electron microscopy, then spatial resolution is improved, but local charging of insulating materials causes imaging artefacts
Solution Approach 1:
The light microscope serves as an intermediary for determining optimal electron microscope parameters including acceleration voltage, beam current, and scan settings. By using the light microscope to pre-characterize the sample and identify regions of interest, the electron microscope can be configured with appropriate parameters that minimize charging effects while maintaining high spatial resolution
Solution Approach 2:
The system enables optimization of electron microscope parameters based on light microscope observations. By changing parameters such as beam current, acceleration voltage, and scan speed based on preliminary light microscopy characterization, the system achieves high spatial resolution while minimizing local charging artefacts in insulating materials
3Measurement precision
If electron beam irradiation is used for imaging, then nanometer-scale resolution is achieved, but chemical reactions and decomposition occur in vulnerable materials
Solution Approach 1:
The light microscope acts as an intermediary that enables complete sample characterization and electron microscope parameter optimization without electron beam exposure. This preliminary optical characterization allows the electron microscope to be configured for direct high-resolution imaging with minimal beam exposure, preventing chemical reactions and decomposition in vulnerable organic and biological materials
Solution Approach 2:
Complete preliminary characterization including sample navigation, region-of-interest identification, and electron microscope parameter determination is performed using the light microscope before any electron beam exposure. This enables the electron microscope to capture high-resolution images with minimal exposure time, preventing cumulative damage from repeated scanning and chemical decomposition in radiation-sensitive materials
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 high-resolution imaging of vulnerable samples without prior electron beam exposure, reducing imaging artefacts and sample modification by optimizing SEM parameters and monitoring for damage in real-time.
Implementation Method 1
capturing a light microscopy image of the sample in its position for imaging with the scanning electron microscope
Implementation Method 2
capturing a scanning electron microscope image of the region of interest in the sample
Data Source
AI summary
The invention relates to a method for inspecting a sample with an assembly comprising a scanning electron microscope (SEM) and a light microscope (LM). The assembly comprises a sample holder for holding the sample. The sample holder is arranged for inspecting the sample with both the SEM and the LM, preferably at the same time. The method comprising the steps of: capturing a LM image of the sample in its position for imaging with the SEM; determining a position and dimensions of a region of interest in or on the sample using the LM image; determining values to which the SEM parameters need to be set to image the sample at a desired resolution; and capturing a SEM image of the region of interest, preferably using the first electron beam exposure of said region of interest.