Focused Ion Beam Cross-Section Alignment for Semiconductor Patterns
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Solution Overview
Problem
Conventional methods struggle to accurately expose cross-sections along the arrangement direction of fine device patterns in semiconductor devices due to the increasing fineness and density of these patterns, making it difficult to align the cross-section formation with the device pattern during analysis.
Innovation Solution
A sample preparation method and apparatus that allows for real-time adjustment of the focused ion beam's scanning direction while observing the sample under a scanning electron microscope, enabling precise alignment and exposure of cross-sections along the device pattern arrangement direction, even for patterns with features in the order of several tens of nanometers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional cross-section processing methods are used, then the device pattern can be observed, but the cross-section cannot be accurately aligned with the arrangement direction of fine device patterns
Solution Approach 1:
The patent implements real-time feedback by displaying the observed image on a display unit during FIB irradiation and allowing the operator to adjust the scanning direction of the FIB based on the observed device pattern arrangement. This closed-loop feedback mechanism enables accurate alignment of the cross-section with the device pattern arrangement direction, resolving the contradiction between manufacturing precision and measurement difficulty.
2Manufacturing precision
If the focused ion beam scanning direction is fixed, then the processing is simple, but the cross-section cannot be adjusted to match the device pattern arrangement direction
Solution Approach 1:
The patent introduces dynamic adjustability of the FIB scanning direction by providing a rotation angle input unit and scanning direction control unit that can change the scanning direction during processing. This dynamic control system allows the scanning direction to be adapted in real-time to match the device pattern arrangement, achieving high alignment accuracy without excessive complexity.
3Productivity
If the device pattern size is reduced and density is increased, then the device integration is improved, but the ability to check and align with the device pattern arrangement direction deteriorates
Solution Approach 1:
The patent introduces an electron beam observation system as an intermediary that provides high-resolution imaging of the device pattern arrangement direction. This intermediary observation system enables precise measurement and alignment even for fine device patterns with reduced size and increased density, overcoming the limitation of direct visual inspection.
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 accurate formation of cross-sections along the device pattern arrangement direction, facilitating detailed analysis of internal structures and defects, and allowing for efficient preparation of samples for both cross-section observation and transmission electron microscope analysis.
Implementation Method 1
subjecting the first cross-section to etching processing by scanning and irradiation of a focused ion beam
Implementation Method 2
an electron beam column configured to scan and irradiate the cross-section with an electron beam; a charged particle detector configured to detect a charged particle emitted from the cross-section by irradiation of the electron beam
Data Source
AI summary
A sample preparation method is carried out using a focused ion beam and an electron beam. While displaying a SEM image of a first cross-section of a sample on a display screen, the first cross-section is subjected to etching processing by scanning and irradiation of the focused ion beam, thereby exposing a second cross-section, and while displaying a SEM image of the second cross-section on the display screen, the scanning direction of the focused ion beam is changed while performing scanning and irradiation of the focused ion beam and subjecting the second cross-section to etching processing, thereby exposing a desired cross-section of the sample.