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Nanosensor Laboratory
Published in Vinod Kumar Khanna, Nanosensors, 2021
What does LIGA stand for? LIGA is an acronym representing the main steps of the process steps involved, i.e., deep XRL, electroforming (a metal-forming process that forms thin parts through the electroplating process, differing from electroplating in that the plating is much thicker and can exist as a self-supporting structure), and plastic molding (a process used in manufacturing to shape materials), in German: Lithographie, Galvanoformung, Abformung (Figure 3.20). By deep XRL, structures of lateral design with high aspect ratios are produced, that is, with heights of up to 1 mm and lateral resolution down to 0.2 μm. The transparent carrier of the mask is a thin metal foil (e.g., titanium, Ti, and beryllium, Be). The absorbers consist of a comparatively thick layer of Au. Synchrotron (cyclic particle accelerator) radiation is employed to transfer the lateral structural information into a plastic layer, generally polymethylmethacrylate (PMMA), (C5O2H8)n. Exposure to radiation modifies the plastic material in such a way that it becomes removable with a suitable solvent, leaving behind the structure of the unirradiated plastic as the primary structure. LIGA process: (a) exposure, (b) developing, and (c) electroplating and removing photoresist. (Khanna, V. K., Proceedings of IMS-2007, Trends in VLSI and Embedded Systems, Punjab Engineering College, Chandigarh, 317, 2007.)
Mechanical Micromachines and Microsystems
Published in George K. Knopf, Kenji Uchino, Light Driven Micromachines, 2018
LIGA is a German acronym standing for lithographie (lithography), galvanoformung (plating), and abformung (molding). However, in practice LIGA essentially stands for a process that combines extremely thick-film resists (often >1 mm thick) and high-energy X-ray lithography (∼1 GeV), which can pattern thick resists with high fidelity and also results in vertical sidewalls. Although some applications may require only the tall patterned resist structures themselves, other applications benefit from using the thick resist structures as plating molds (i.e., material can be quickly deposited into a highly detailed mold by electroplating). A drawback to LIGA is the need for high energy X-ray sources (e.g., synchrotrons or linear accelerators) that are very expensive.
Fabrication of BioMEMS Devices
Published in Simona Badilescu, Muthukumaran Packirisamy, BioMEMS, 2016
Simona Badilescu, Muthukumaran Packirisamy
The LIGA technology is used largely in the fabrication of biomedical devices (Figure 7.21). This German acronym means lithography, electroplating, and molding. The process can be used for manufacturing high-aspect-ratio three-dimensional microstructures in a wide variety of materials, such as metals, polymers, ceramics, and glasses. It relies on the use of high-energy x-rays from a synchrotron to induce damage in the molecules of a sensitive resist. After exposure to the radiation, these regions may be selectively etched by a chemical solvent, and the remaining structure may be replicated by a number of electroplating or casting processes.
Investigation of the enhancement of microelectromechanical capacitive pressure sensor performance using the genetic algorithm optimization technique
Published in Engineering Optimization, 2021
Mohamed M. Y. B. Elshabasy, Mohamed A. Al-Moghazy, Hassan A. El Gamal
Because of the possible complexity, the possibility of a high aspect ratio and the tininess of the proposed sensor in the current investigation, the fabrication feasibility and other related challenges are surveyed. Among the various MEMS fabrication processes, the additive manufacturing (AM) techniques are an outstanding class. Over the past decade, there has been huge progress in the techniques of AM for both MEMS and, more recently, nanoelectromechanical systems (NEMS). Among these techniques are high-aspect-ratio microfabrication techniques such as lithography electroforming and moulding (Lithography Galvanoformung and Abformung or LIGA). This technique allows for the fabrication of miniaturized complex structures, such as gears, probes, springs and moulded nozzle plates for inkjet printers, with high aspect ratios (Prime Faraday Partnership 2002). Comparing the profile proposed in the current investigation with the complex micro- and nano-components listed above, the manufacturing process is relatively feasible. Yoon et al. (2014), Ingarao et al. (2018) and Li et al. (2018) have investigated the technical, economic and environmental challenges of these AM techniques compared to other manufacturing techniques.
Optimization of photochemical machining process parameters for manufacturing microfluidic channel
Published in Materials and Manufacturing Processes, 2019
Devendra Agrawal, Dinesh Kamble
Microfluidics deal with the study of fluid behavior through microchannels and the technology of manufacturing microminiaturized devices containing chambers and tunnels through which fluids flow. The application of two immiscible fluids mixing in microchannel is increasing in many industrial fields like cooling of electronic device, biomedical, MEMS, and micro-refrigeration systems. Mixing of fluid is a slow process and mainly depends on molecular diffusion; hence, microchannels are desired for complete mixing with laminar flow.[1] These microchannels are manufactured by the techniques, such as lithography, laser ablation, LIGA, µ-EDM, electron beam machining, and X-ray lithography. These methods are having disadvantages in high cost, necessity of clean rooms, and limited control over the surface properties also take long time to convert design in to the prototype hence found to be inaccessible techniques for biologists. These disadvantages limit the interest of the industrial community toward its use. It increases the search of effective low-cost machining process with control over above drawbacks.[2,3]
Electrode wear phenomenon and its compensation in micro electrical discharge milling: A review
Published in Materials and Manufacturing Processes, 2018
Siddhartha Kar, Promod Kumar Patowari
Die sinking µEDM is the most crucial technology used in the manufacturing of mold insert.[54] It is primarily used in the production of replica tools for the large-scale production of micromechanical parts.[25] Electrode act as the positive impression of the required shape whose final impression would resemble the negative geometry/image of the electrode.[55,56] The principal challenge lies in the manufacturing of the structured tool electrode and compensating the TW to achieve dimensional accuracy of machined cavity.[56] Manufacturing of such electrode is complex and expensive.[49,57] Machining is a way to produce a structured electrode, but the size is limited to the available tools in the market. Lithography, electroplating, and molding (LIGA) and laser sintering are some of the most viable technologies that can be used in manufacturing of structured tool electrodes.[58,59] WEDM also provides an alternative process for fabrication of tool but producing sculptured surface is very difficult.[54] Rotation of tool electrode is avoided in die sinking because rotation would nullify the sculpture shape and produce a circular cavity. Relative wear can be more than 30% in die sinking µEDM which impels the use of high wear resistant composite materials like tungsten-copper, cemented carbide, etc.[25]