Composite Charged Particle Beam Apparatus for FIB-GIB Sample Processing
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Solution Overview
Problem
The existing technologies for preparing thin samples using focused ion beam (FIB) apparatuses often result in a 'curtain effect' due to varying etching rates, leading to convex-concave portions on the observation surface, which affects the observation image, especially for advanced semiconductor devices with fine structures.
Innovation Solution
A composite charged particle beam apparatus is developed, comprising a first and second charged particle beam column, a sample stage, and tilt units to tilt the sample, allowing for controlled irradiation with focused and gas ion beams from different angles, enabling precise finishing processing and reducing streaks in the observation image.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If gas ion beam finishing processing is performed to remove damaged layers, then the quality of thin sample is improved, but convex-concave portions are formed on the observation surface causing curtain effect
Solution Approach 1:
The invention introduces a second tilt axis (azimuth tilt) in addition to the first tilt axis (elevation tilt), transforming the sample stage from single-axis to dual-axis tilting capability. This dimensional expansion allows irradiation from multiple azimuthal directions, effectively suppressing convex-concave formation by distributing etching effects across different angles while maintaining damaged layer removal quality.
2Manufacturing precision
If ion beam finishing processing is applied to advanced semiconductor devices with fine structures, then damaged layers are removed, but streaks appear in observation images due to varying etching rates
Solution Approach 1:
By adding azimuthal tilting capability around a second tilt axis, the system enables multi-directional irradiation that averages out etching rate variations across different materials. This dimensional enhancement allows the ion beam to approach the sample from multiple azimuthal angles, suppressing streak formation while effectively removing damaged layers from fine semiconductor structures.
Solution Approach 2:
The invention dynamically changes the irradiation angle parameters by tilting the sample stage around both elevation and azimuth axes. By varying the azimuthal angle in addition to the elevation angle, the system adjusts the beam-sample interaction parameters to minimize etching rate differences between various materials, thereby reducing streak artifacts in observation images while maintaining effective damaged layer removal.
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 effectively suppresses the 'curtain effect' and minimizes streaks in the observation image, allowing for clearer visualization of the device structure and defects, even for fine structures, by adjusting the tilt and irradiation angles during the processing.
Implementation Method 1
forming a cross-sectional surface on a thin sample by irradiating the thin sample with a first charged particle beam
Implementation Method 2
performing first finishing processing by irradiating the cross-sectional surface with a second charged particle beam
Data Source
AI summary
A composite charged particle beam apparatus includes a FIB column for irradiating a thin sample with a FIB and a GIB column for irradiating the thin sample with a GIB. The thin sample is placed on a sample stage, and a tilt unit tilts the thin sample about a tilt axis of the sample stage, the tilt axis being orthogonal to the FIB irradiation axis and being located inside a plane formed by the FIB irradiation axis and the GIB irradiation axis. A tilt sample holder is mounted on the sample stage and fixes the thin sample such that a cross-sectional surface of the thin sample is tilted at a constant angle with respect to the GIB irradiation axis and the azimuth angle of the GIB column can be changed by rotation of the sample stage.