In a major leap forward for microscopic imaging, a team of researchers has unveiled an innovative technique designed to capture the three-dimensional morphology of micro-structures that have been notoriously difficult to characterize. This method, termed Fourier ptychographic coherence scanning interferometry (FPCSI), promises to transform the study of high aspect ratio and composite micro-trenches, opening new frontiers in fields ranging from semiconductor manufacturing to advanced materials science.
Micro-trenches, tiny grooves etched into materials, play a critical role in various high-tech applications. Their precise three-dimensional morphology dictates key properties such as electronic performance, mechanical strength, and fluid dynamics on microscale devices. Yet, traditional imaging methods have struggled to achieve comprehensive, high-resolution measurements of structures with high aspect ratios—those with depths significantly larger than their width—due to limitations in focus depth and resolution.
The newly developed FPCSI technique addresses these challenges by combining the power of Fourier ptychography with coherence scanning interferometry. Fourier ptychography itself is a computational imaging method that synergistically uses multiple low-resolution images captured under varying illumination angles to synthesize high-resolution images free of the limitations imposed by conventional optics. Meanwhile, coherence scanning interferometry is a well-established optical technique for measuring surface topography with nanometric precision.
By fusing these two approaches, the research team has effectively created a hybrid system capable of resolving complex micro-trench geometries with unprecedented clarity. The method exploits the coherent nature of light and computational reconstruction algorithms to extract phase information, which, when analyzed across different focal positions, renders a high-fidelity 3D image. This allows for the meticulous profiling of microstructures, including deep trenches and composite formations that were previously inaccessible.
In demonstrating the efficacy of FPCSI, the researchers meticulously investigated micro-trenches with aspect ratios far exceeding those measurable by existing solutions. Their approach yielded precise depth maps and surface profiles, revealing subtle features within the trenches that conventional microscopy would miss. This opens doors to better quality control and design optimization in semiconductor fabrication, where such trench structures are ubiquitous.
Furthermore, the technique’s non-destructive nature stands out as particularly advantageous. Unlike methods requiring physical sectioning or those employing harsh probing tools, FPCSI operates purely through optical means, preserving the integrity of delicate samples. This characteristic is crucial in research and industry where every sample holds significant value and must remain unaltered for subsequent analysis or functional use.
The ability to characterize composite micro-trenches—those composed of multiple materials or layers—adds another dimension to the method’s versatility. Different materials often exhibit unique refractive indices and scattering properties, complicating optical measurements. FPCSI leverages its coherent scanning framework to differentiate between these layers, providing a detailed morphological map that elucidates structural composition as well as geometry.
Technically, the process involves scanning a sample through multiple focus positions while illuminating it under varying incident angles. The resulting dataset, rich in both amplitude and phase information, is then processed through iterative algorithms rooted in Fourier ptychography principles. These algorithms reconstruct high-resolution images and precise depth profiles from what would otherwise be fragmented or blurred data, overcoming classical optical trade-offs between resolution and depth of field.
The impact of this innovation stretches beyond just micro-trenches. The researchers envision applications in microfluidics, biomedical devices, and nanofabrication, where accurate morphological characterization is essential. For instance, in microfluidics, the precise dimensions of channels and reservoirs influence fluid flow dynamics and reaction rates; FPCSI could provide a powerful tool for designing and validating such devices with greater efficiency.
Another promising avenue lies in the realm of materials science, particularly in the inspection of composite materials and layered structures. FPCSI’s sensitivity to phase variations makes it an excellent candidate for evaluating internal morphologies and detecting sub-surface defects that traditional imaging struggles to resolve.
While the technique is computationally intensive, advances in processing power and algorithm optimization have made it increasingly accessible. The researchers have implemented efficient codebases and integrated machine learning strategies to accelerate image reconstruction, envisioning real-time or near-real-time imaging capabilities in future iterations.
Despite the successes, the team acknowledges certain limitations. The requirement for controlled illumination angles and precise scanning mechanisms can pose experimental challenges. Furthermore, complex surface reflections and multiple scattering in highly irregular structures might still introduce artifacts. However, ongoing refinements in hardware and software are expected to mitigate these issues.
The paper detailing the development and validation of FPCSI represents a significant contribution to optical microscopy and metrology. By cleverly integrating established methods into a cohesive and powerful imaging tool, the researchers have carved out a new pathway for detailed, non-invasive exploration of microscale features that were, until now, elusive.
Ultimately, the innovation not only fills a technical gap but also paves the way for enhanced quality assurance, novel device design, and deeper scientific understanding across multiple disciplines. As the digital and physical worlds continue to converge at micro- and nano-scales, tools like Fourier ptychographic coherence scanning interferometry will become instrumental in shaping the next wave of technological advancement.
The versatility and precision of FPCSI underscore the increasing importance of interdisciplinary approaches, combining optics, computational imaging, and materials science. This convergence reflects a broader trend toward harnessing light’s coherent properties alongside algorithmic ingenuity, positioning this technique at the forefront of imaging science innovation.
In an era where micro- and nano-fabrication is integral to numerous industries, the ability to fully characterize complex internal structures without destruction or compromise is invaluable. FPCSI fulfills this need with elegance and efficiency, promising to become a standard in advanced optical metrology.
Continued research and development will likely enhance the technique’s robustness, reduce its dependence on idealized sample preparation, and expand its applicability to a wider array of materials and geometries. The vision of capturing intricate 3D micro-morphologies in real time is now closer than ever, thanks to this breakthrough.
By unlocking new dimensions of imaging capacity, Fourier ptychographic coherence scanning interferometry stands to accelerate innovation in microelectronics, photonics, and beyond, echoing the ever-growing demand for precision and detail at the smallest scales of technology and nature.
Subject of Research:
Three-dimensional morphological characterization of high aspect ratio and composite micro-trenches.
Article Title:
Fourier ptychographic coherence scanning interferometry for 3D morphology of high aspect ratio and composite micro-trenches.
Article References:
Li, Y., Yuan, Q., Huo, X. et al. Fourier ptychographic coherence scanning interferometry for 3D morphology of high aspect ratio and composite micro-trenches. Light Sci Appl 15, 93 (2026). https://doi.org/10.1038/s41377-026-02189-6
Image Credits: AI Generated
DOI: 29 January 2026
Tags: 3D micro-trench imagingadvanced materials science applicationscomputational imaging methodselectronic performance analysisFourier ptychographic interferometryhigh aspect ratio imaginginnovative imaging techniquesmechanical strength characterizationmicro-structure characterizationnanometric precision measurementsoptical techniques for surface topographysemiconductor manufacturing techniques
