Femtika Laser Nanofactory SLE: Selective Laser Etching

General Introduction

The Femtika Laser Nanofactory SLE model is a femtosecond laser subtractive‑manufacturing system specialized in fabricating three‑dimensional microstructures within transparent, brittle materials, particularly glass. It primarily employs a process that combines femtosecond laser‑induced modification with chemical etching, enabling high‑precision 3D patterning of materials such as fused silica and borosilicate glass. Unlike conventional glass‑processing techniques, the SLE technology can create predefined features—such as micropores, deep holes, internal channels, cavities, and complex 3D geometries—at arbitrary locations inside the glass matrix, all while preserving the material’s surface integrity. This makes it especially well suited for fabricating micro‑devices that demand exceptional chemical stability, optical transparency, and mechanical strength. The system finds broad applications in glass‑based microfluidic chips, integrated optics, microsensors, biochips, and micro‑optomechanical devices. It excels at producing structures with high aspect ratios, addressing challenges associated with traditional machining, sandblasting, and wet‑chemical etching that struggle to achieve intricate internal 3D architectures. The equipment also features a highly stable granite frame, precision translation stages, and a galvanometer‑based scanning system, complemented by a femtosecond laser source and an integrated real‑time monitoring system, ensuring precise and controllable modification paths within the glass. The SLE model delivers outstanding performance in research and small‑batch prototyping, enabling rapid development of glass‑based prototypes and providing universities, research institutes, and related enterprises with a comprehensive solution—from process validation to sample fabrication. With its mature processes and excellent reproducibility, coupled with standardized etching workflows, it consistently yields glass microstructures characterized by clean edges, smooth inner walls, and high dimensional accuracy, 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: the first step involves femtosecond laser‑induced internal modification, and the second step is chemical selective etching. After focusing, the femtosecond laser beam is precisely delivered into the bulk of transparent glass, generating an extremely high energy density at the focal spot. This induces irreversible local modifications to the glass structure—such as lattice disorder, bond breaking, and density changes—creating modified channels that exhibit markedly different physicochemical properties compared to the unmodified regions. Owing to the ultrashort duration of the femtosecond pulses, the heat‑affected zone is minimal, preventing glass cracking or overall 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 subsequent etching. In the second step, the laser‑processed glass is immersed in an etchant—typically dilute hydrofluoric acid or a related etching solution. A pronounced difference in etch rates exists between the modified and unmodified areas: the modified portions are rapidly removed, while the unmodified regions remain largely unaffected, yielding pre‑designed three‑dimensional pore, groove, or cavity structures. By tuning laser parameters, scan paths, and etching time, one can precisely control feature dimensions, aspect ratios, and surface quality. The equipment is equipped with automatic focusing and vision‑based positioning systems, ensuring stable focus at various depths within the glass and mitigating positioning errors arising from refractive index variations or sample thickness. Field‑of‑view scanning enables continuous processing of large‑area glass substrates without the need for repeated alignment and stitching, enhancing overall throughput and structural integrity. The resulting glass microstructures feature smooth inner walls, zero residual stress, and no burrs, making them suitable for direct application in microfluidics, optical transmission, pressure sensing, and other advanced technologies.

Advantages and Key Features

The SLE process is distinguished by its ability to fabricate true three-dimensional structures within transparent glass, a capability that sets it apart from conventional glass machining, which is limited to surface‑level operations. It enables the creation of closed channels, intersecting passageways, and multilayer interconnected architectures, significantly expanding the design space for glass‑based devices. Furthermore, this technology supports extremely high aspect ratios—outperforming standard drilling and photolithography—making it well suited for fabricating slender microchannels and high‑precision microholes. The fabrication process is non‑contact, avoiding mechanical stress, chipping, or scratching on the glass surface, thereby preserving sample surface integrity and optical performance. Femtosecond laser modification generates minimal thermal damage, reducing the likelihood of microcracks and enhancing structural strength and stability, which is particularly advantageous for demanding biological and optical applications. The equipment exhibits excellent compatibility with common optical glasses, including fused silica and borosilicate glass—materials that offer superior chemical stability, high‑temperature resistance, and good biocompatibility, making them suitable for a wide range of applications. The SLE process is fully compatible with conventional microfabrication techniques, facilitating seamless integration with existing chip packaging and bonding workflows, thus supporting monolithic device development. The system delivers 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 minimizes human intervention and enhances process robustness. Compared with purely mechanical machining, SLE is better equipped to handle complex internal geometries; and when contrasted with traditional wet etching, it offers superior spatial selectivity and greater three‑dimensional controllability, conferring clear technical advantages in glass‑based microfluidics and integrated optics. The overall design balances research flexibility with stable small‑batch production, making it ideal for long‑term, reliable operation.

Application Areas and Use Cases

SLE‑based devices are primarily employed in areas such as glass microfluidic chips, integrated optics, micro‑opto‑electromechanical systems, biomedical diagnostics, and high‑pressure fluidic components. Glass exhibits strong chemical inertness, excellent optical transparency, and superior resistance to high temperatures, acids, and bases, making it an ideal substrate for advanced microfluidic chips. SLE technology enables the fabrication of intricate three‑dimensional network channels, suitable for cell culture, nucleic acid analysis, drug screening, and environmental monitoring. In the realm of integrated optics, glass can be used to fabricate on‑chip waveguides, beam splitters, resonators, and microcavity structures, which find applications in optical sensing, laser devices, and optical communication modules. In the field of micro‑optomechanics, the high mechanical strength of glass facilitates the creation of microsensors, pressure‑sensing chips, and microfluidic control valves. In biomedicine, glass‑based platforms are commonly utilized to manufacture implantable device substrates, cell‑observation chips, and high‑throughput assay chips, offering long‑term stable operation with minimal risk of contamination. Notable examples include research institutions that employ SLE to process fused silica microfluidic chips, enabling the separation of blood components and the execution of microscale chemical reactions; other teams have leveraged high aspect‑ratio microporous arrays to develop highly efficient filters and detection probes for analyzing trace amounts of gases or liquids. In optics, researchers utilize internally modified structures to fabricate passive optical components, enhancing system integration and stability. Moreover, this technology has found utility in sensor development, where precision internal architectures in glass enable highly sensitive measurements of physical parameters such as pressure, flow rate, and refractive index.