Focused Ion Beam Cross Section Processing for Organic Samples
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Solution Overview
Problem
The challenge in processing cross sections of samples with focused ion beams is the damage caused to organic substances like resist films due to fluctuations in etching speed and deformation, which hinders accurate observation, especially when using FIB for SEM or TEM samples with micropatterns.
Innovation Solution
A method involving a protective film forming step using a focused ion beam under specific accelerating voltages, followed by cross section processing at higher voltages, to minimize damage and ensure accurate cross-section acquisition, including the use of different ion species and beam angles for effective protection and processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If cross section processing is performed directly on samples with organic substance layers using FIB, then processing can be done quickly, but the organic substance becomes damaged and deformed by the ion beam
Solution Approach 1:
A protective film is formed on the organic substance layer before cross section processing to prevent ion beam damage. The protective film is deposited in advance to shield the organic material during subsequent FIB etching, allowing direct processing without damage to the underlying structure
Solution Approach 2:
A protective film acts as an intermediary layer between the ion beam and the organic substance. This intermediate layer absorbs the harmful effects of the ion beam while allowing the processing to continue, protecting the organic material from direct exposure to damaging radiation
2Ease of manufacture
If protective film is formed on the sample before cross section processing by electron beam, then processing can be done, but the organic substance on the sample is deformed
Solution Approach 1:
The electron beam-based protective film formation is replaced with a deposition-based process. This substitution eliminates the deformation caused by electron beam irradiation while still achieving protective film formation, using a different physical mechanism that does not damage the organic material
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 reduces ion beam damage to organic substances, enabling high-accuracy cross-section processing and preservation of sample integrity for precise observation and TEM sample fabrication.
Implementation Method 1
forming a protective film on the surface of the layer or the structure of the organic substance by irradiating the surface of the sample including the cross section processing position with the focused ion beam under the existence of source gas as the protective film
Implementation Method 2
performing cross section processing by irradiating the cross section processing position formed with the protective film with the focused ion beam at a voltage higher than an accelerating voltage in the protective film forming step
Data Source
AI summary
A cross section processing method to be performed on a sample by irradiating the sample having a layer or a structure of an organic substance on a surface at a cross section processing position thereof with a focused ion beam using a focused ion beam apparatus includes: a protective film forming step for forming a protective film on the surface of the layer or the structure of the organic substance by irradiating the surface of the sample including the cross section processing position with the focused ion beam under the existence of source gas as the protective film; and a cross section processing step for performing cross section processing by irradiating the cross section processing position formed with the protective film with the focused ion beam at a voltage higher than an accelerating voltage in the protective film forming step.