Femtika Laser Nanofactory SLE Selective Laser Etching

General Introduction

The Femtika Laser Nanofactory SLE model is a femtosecond laser subtractive manufacturing system specialized in the fabrication of three-dimensional microstructures within transparent, brittle materials, particularly glass. It primarily employs a hybrid process combining femtosecond laser–induced modification with chemical etching to achieve high-precision 3D etching of materials such as fused silica and borosilicate glass. Unlike conventional glass-processing methods, SLE technology can create pre-defined internal structures at arbitrary locations within the glass bulk, including micropores, deep holes, internal channels, cavities, and complex 3D geometries, while preserving the integrity of the material’s surface—making it especially well suited for fabricating microdevices that demand high chemical stability, optical transparency, and mechanical strength. This equipment finds broad applications in glass-based microfluidic chips, integrated optics, microsensors, biochips, and micro-optomechanical systems, enabling the fabrication of structures with high aspect ratios and overcoming the challenges of achieving intricate internal 3D features that are difficult or impossible to attain through traditional machining, sandblasting, or wet etching. The system also features a highly stable granite frame, high-precision translation stages, and a galvanometer-based scanning architecture, coupled with a femtosecond laser source and a real-time monitoring system, to ensure precise and controllable modification paths within the glass. The SLE model excels in research and small-batch prototyping scenarios, allowing rapid development of glass-based prototypes and providing universities, research institutes, and related enterprises with a comprehensive solution spanning process validation to sample fabrication. With its mature processes and excellent reproducibility, combined with standardized etching procedures, it consistently produces glass microstructures with well-defined edges, smooth inner walls, and high dimensional uniformity, making it a key piece of equipment in the field of glass micro- and nano-fabrication.

Working Principle

SLE selective laser etching operates via a two-step process: first, femtosecond laser–induced internal modification; second, chemically mediated selective etching. After focusing, the femtosecond laser beam is precisely delivered into the bulk of transparent glass, where it generates an extremely high energy density at the focal spot, inducing irreversible modifications to the local glass structure—such as lattice disorder, bond breaking, and density changes—and thereby creating modified channels that exhibit markedly different physicochemical properties from the unmodified regions. Owing to the ultrashort duration of the femtosecond pulses, the heat-affected zone is minimal, precluding glass cracking or bulk thermal deformation. The system employs a CNC platform and galvanometer scanners to steer the laser focus within the glass according to a three-dimensional model, thereby fabricating continuous modified regions that are preferentially dissolved during the subsequent etching step. In the second step, the laser-treated glass is immersed in an etchant—typically dilute hydrofluoric acid or a related etching formulation—where the modified and unmodified areas display distinct etching rates: the modified portions are rapidly removed by corrosion, while the unmodified regions remain virtually unaffected, thus forming the desired three-dimensional pore, groove, or cavity structures. By carefully tuning laser parameters, scan paths, and etching time, the dimensions, aspect ratio, and surface quality of the fabricated features can be precisely controlled. The equipment is equipped with an automatic focusing and vision-based positioning system that ensures stable focus at varying depths within the glass, mitigating positioning errors arising from refractive-index variations or sample thickness. Furthermore, the infinite-field-of-view scanning capability enables continuous processing of large-format glass substrates without the need for repeated alignment and tiling, thereby enhancing overall processing efficiency and structural continuity. The resulting microstructures exhibit smooth inner walls, zero residual stress, and no burrs, making them suitable for direct application in microfluidics, optical waveguiding, pressure sensing, and other advanced applications.

Advantages and Key Features

The most distinctive feature of the SLE process is its ability to fabricate true three-dimensional structures within transparent glass, breaking through the conventional limitation that glass processing is confined to the surface. This enables the creation of closed channels, intersecting pore networks, and multilayer interconnected architectures, thereby dramatically expanding the design space for glass-based devices. Furthermore, the technology supports extremely high aspect ratios—far surpassing those achievable with conventional drilling and photolithography—making it ideally suited for fabricating slender microchannels and high-precision microholes. The fabrication process is non-contact, eliminating mechanical stress, chipping, or scratching on the glass surface and ensuring the integrity of the sample’s surface and its optical performance. Femtosecond laser modification results in minimal thermal damage, reducing the likelihood of microcracking and enhancing structural strength and stability, which makes it particularly suitable for biocompatible and optically demanding applications with stringent reliability requirements. The equipment exhibits excellent compatibility with commonly used optical glasses, including fused silica and borosilicate glass—materials that offer strong chemical stability, high-temperature resistance, and good biocompatibility, thus supporting a wide range of applications. The SLE process is also compatible with conventional microfabrication techniques, facilitating seamless integration with existing chip packaging and bonding workflows and enabling the development of fully integrated devices. The system boasts high positioning accuracy and precise path control, ensuring uniform channel dimensions, minimal positional deviations, and excellent batch-to-batch repeatability. Coupled with automated monitoring and parameter management, it reduces human intervention and enhances process stability. Compared with purely mechanical machining, SLE is better suited for complex internal structures; and compared with traditional wet etching, it offers superior spatial selectivity and greater three-dimensional controllability, conferring clear technical advantages in the fields of glass-based microfluidics and integrated optics. The overall design balances research flexibility with stable small-batch production, making it well-suited for long-term, reliable operation.

Application Areas and Use Cases

SLE technology is primarily employed in fields such as glass microfluidic chips, integrated optics, micro-opto-electro-mechanical systems, biomedical diagnostics, and high-pressure fluidic devices. Glass’s strong chemical inertness, excellent optical transparency, and outstanding resistance to high temperatures, acids, and alkalis make it an ideal substrate for high-end microfluidic chips; SLE enables the fabrication of complex three-dimensional network channels for applications including cell culture, nucleic acid analysis, drug screening, and environmental monitoring. In the realm of integrated optics, SLE can be used to fabricate on-chip waveguides, beam splitters, resonant cavities, and microcavity structures for optical sensing, laser components, and optical communication modules. In the micro-opto-mechanical domain, the high strength of glass allows for the creation of microsensor structures, pressure chips, and microfluidic control valves. In biomedicine, SLE is commonly utilized to manufacture substrates for implantable devices, cell-imaging chips, and high-throughput diagnostic chips, enabling long-term stable operation with minimal risk of contamination. Notable examples include research institutions that use SLE to process fused quartz microfluidic chips for blood-component separation and microscale chemical reactions, as well as research teams that employ high aspect-ratio microporous arrays to fabricate highly efficient filters and detection probes for trace gas or liquid analysis. In optics, researchers leverage internally modified structures to produce passive optical components, thereby enhancing system integration and stability. Moreover, this technology finds application in the development of advanced sensors, where precision internal structures in glass enable highly sensitive detection of physical parameters such as pressure, flow rate, and refractive index. SLE effectively addresses the industry challenge of glass’s inherent difficulty in undergoing complex internal processing, driving the evolution of glass-based functional devices from simple architectures toward greater integration, miniaturization, and three-dimensionality.