Computational Adaptive Optics for HAR Hybrid Trench Array Topography Measurement by Utilizing Coherence Scanning Interferometry
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View abstract on PubMed
Summary
This summary is machine-generated.This study introduces a computational method using particle swarm optimization (PSO) to correct aberrations in coherence scanning interferometry (CSI) for high aspect ratio (HAR) structures. The technique accurately measures topography in complex hybrid trench arrays without prior data.
Area Of Science
- Optical Metrology
- Nanotechnology
- Computational Imaging
Background
- Coherence scanning interferometry (CSI) struggles with aberrations from high aspect ratio (HAR) samples, hindering accurate topography measurement of microstructures.
- Existing aberration correction methods using deformable mirrors are insufficient for shift-variant aberrations in hybrid trench arrays with varying parameters.
Purpose Of The Study
- To develop a novel computational aberration correction method for precise topography measurement of HAR structures using CSI.
- To address the limitations of previous methods in compensating for shift-variant aberrations in complex hybrid trench arrays.
Main Methods
- A computational aberration correction method employing the particle swarm optimization (PSO) algorithm is proposed, eliminating the need for databases or prior knowledge.
- A spatial frequency domain phase filter is constructed to restore interference signals distorted by shift-variant aberrations.
- A multi-channel aberration correction scheme using virtual phase filters, based on isoplanatic region segmentation, is established for hybrid trench array samples.
Main Results
- The PSO algorithm successfully derives optimal Zernike polynomial coefficients for the phase filter, using interference fringe contrast as the optimization criterion.
- A window function derived from the 3D transfer function (3D-TF) bandwidth is used to preprocess interferograms, filtering out extraneous signals.
- Experimental validation on single and hybrid trench samples (depths 100-300 μm, widths 10-30 μm) confirms the method's effectiveness and accuracy.
Conclusions
- The proposed computational aberration correction method accurately measures HAR structure topography, even in challenging hybrid trench arrays.
- The isoplanatic region segmentation and PSO-based virtual phase filtering offer a robust solution for shift-variant aberration compensation in CSI.
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