Optimization of laser machining process for the preparation of photomasks, and its application to microsystems fabrication
01 Jan 2014-Journal of Micro-nanolithography Mems and Moems (International Society for Optics and Photonics)-Vol. 12, Iss: 4, pp 041203-041203
TL;DR: In this paper, a strategy of high-throughput manufacturing of hard masks with laser micromachining using a one-step exposure process of a chromated glass slide through a micro-achined aluminum shadow mask is proposed.
Abstract: Conventional photolithography normally utilizes a photomask for patterning light onto a chemical resist film. Therefore, the accuracy of microfabrication is highly dependent on the accuracy of the photomasks. Fabrication of hard masks involves the use of expensive laser pattern generators and other sophisticated machines using very high-precision stages and the necessary control instrumentation; therefore, an inexpensive strategy is highly necessary for laboratory-level fabrication. As this technology is primarily based on raster scanning of a laser beam, the mask making as such becomes a low-throughput process. A strategy of high-throughput manufacturing of hard masks with laser micromachining using a one-step exposure process of a chromated glass slide through a micromachined aluminum shadow mask is proposed. The features that are finally embedded in the mask are highly demagnified and well focused. Optimization of the laser machining process is carried out by considering all processing parameters. The features are characterized using an optical microscope, a scanning electron microscope, and a self-developed image analysis code. Geometrical methods are used to estimate the average edge roughness and feature size. We have also validated the usage of these masks by performing microfabrication on films made of photoresist.
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01 Jan 2019
TL;DR: This chapter aims at discussing important MEMS-based sensors and their applications in the automotive-like tire pressure and monitoring systems, engine management system, vehicle stability/passenger safety system, and emission control.
Abstract: The automotive industry has always been an area, where the possibility to explore more and to achieve next-gen technology remains a challenge. As the market is growing, the possibilities are being explored on a wider scale. And these growing possibilities are increasingly demanding the research for the more accurate functioning of the automotive through the use of various sensors and the integration aspects associated with them. While enhancing the quality/performance of the vehicle, the need to reduce the size of sensors always remains a challenge. Over the period of time, the technology has advanced and these challenges are taken care through the use of MEMS (Microelectro mechanical systems) integrated systems. MEMS helps in devising microscale sensors with higher accuracy in small size and low cost. In the automotive, there exists a huge need for these installing these sensors and utilizing them to refine the performance characteristics of the vehicles. This chapter aims at discussing important MEMS-based sensors and their applications in the automotive-like tire pressure and monitoring systems, engine management system, vehicle stability/passenger safety system, and emission control.
27 citations
TL;DR: The integration of microfluidic devices with smartphones and wireless network systems using the Internet-of-things will enable readers for manufacturing advanced POCT devices for remote disease management in low resource settings.
Abstract: Recent advances in microfluidics-based point-of-care testing (POCT) technology such as paper, array, and beads have shown promising results for diagnosing various infectious diseases. The fast and timely detection of viral infection has proven to be a critical step for deciding the therapeutic outcome in the current COVID-19 pandemic, which in turn not only enhances the patient survival rate but also reduces the disease-associated comorbidities. In the present scenario, rapid, noninvasive detection of the virus using low cost and high throughput microfluidics-based POCT devices embraces the advantages over existing diagnostic technologies, for which a centralized lab facility, expensive instruments, sample pretreatment, and skilled personnel are required. Microfluidic-based multiplexed POCT devices can be a boon for clinical diagnosis in developing countries that lacks a centralized health care system and resources. The microfluidic devices can be used for disease diagnosis and exploited for the development and testing of drug efficacy for disease treatment in model systems. The havoc created by the second wave of COVID-19 led several countries’ governments to the back front. The lack of diagnostic kits, medical devices, and human resources created a huge demand for a technology that can be remotely operated with single touch and data that can be analyzed on a phone. Recent advancements in information technology and the use of smartphones led to a paradigm shift in the development of diagnostic devices, which can be explored to deal with the current pandemic situation. This review sheds light on various approaches for the development of cost-effective microfluidics POCT devices. The successfully used microfluidic devices for COVID-19 detection under clinical settings along with their pros and cons have been discussed here. Further, the integration of microfluidic devices with smartphones and wireless network systems using the Internet-of-things will enable readers for manufacturing advanced POCT devices for remote disease management in low resource settings.
25 citations
TL;DR: In this paper, a detailed discussion has been carried out to understand critical steps involved in the fabrication of the silicon-based MEMS resonator and some challenges starting from the materials' selection to the final phase of obtaining a compact MEMS resonance device for its fabrication have been explored critically.
16 citations
TL;DR: A novel cost-efficient method of multi-beam micromachining of invar foil with high precision and almost no thermal effects and heat-affected zone is introduced, thus significantly improving the throughput and efficiency.
Abstract: To fulfil the requirements for high-resolution organic light-emitting diode (OLED) displays, precise and high-quality micrometer-scale patterns have to be fabricated inside metal shadow masks. Invar has been selected for this application due to its unique properties, especially a low coefficient of thermal expansion. In this study, a novel cost-efficient method of multi-beam micromachining of invar will be introduced. The combination of a Meopta beam splitting, focusing and monitoring module with a galvanometer scanner and HiLASE high-energy pulse laser system emitting ultrashort pulses at 515 nm allows drilling and cutting of invar foil with 784 beams at once with high precision and almost no thermal effects and heat-affected zone, thus significantly improving the throughput and efficiency.
14 citations
TL;DR: A comprehensive characterization of a QuikLaze 50ST2 multimodal laser micromachining tool by determining the ablation characteristics of six (6) different materials and demonstrating two applications is presented.
Abstract: Laser micromachining is a direct write microfabrication technology that has several advantages over traditional micro/nanofabrication techniques. In this paper, we present a comprehensive characterization of a QuikLaze 50ST2 multimodal laser micromachining tool by determining the ablation characteristics of six (6) different materials and demonstrating two applications. Both the thermodynamic theoretical and experimental ablation characteristics of stainless steel (SS) and aluminum are examined at 1064 nm, silicon and polydimethylsiloxane (PDMS) at 532 nm, and Kapton® and polyethylene terephthalate at 355 nm. We found that the experimental data aligned well with the theoretical analysis. Additionally, two applications of this multimodal laser micromachining technology are demonstrated: shadow masking down to approximately 1.5 µm feature sizes and interdigitated electrode (IDE) fabrication down to 7 µm electrode gap width.
10 citations
Cites background or methods from "Optimization of laser machining pro..."
...Laser micromachining has occasionally been used for shadow mask fabrication; however, the state of the art in laser micromachining (minimum feature size of 10 μm) [23] (to date) has relied entirely on single-wavelength excimer, CO2, and Nd:YAG (neodymium-doped yttrium aluminum garnet) lasers [1,3,12,23–36]....
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...Shadow masking technology is an integral part of fabricating micro/nanostructures for prototyping in microelectronics, optical, microfluidic, MEMS, packaging, and biomedical lab-on-a-chip applications [11,23]....
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...The organic and inorganic layer patterning can be utilized for applications such as accurate cell placement in single cell and culture assays, precision confinement and growth of cellular constructs, tissue engineering, metal micro/nanoelectrodes, definition of organic insulation layers, and other lab-on-a-chip and diagnostic applications [3,23,41,49,51]....
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...The lasers used in the aforementioned research can produce shadow masks for MEMS applications, but they are unable to micromachine highly precise features on the scale of a single micron, unless they operate in the femtosecond regime [3,7,23,24,30,37]....
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...To the best of our knowledge, this is the lowest feature size demonstrated for laser defined shadow masks [3,23]....
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References
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TL;DR: It is demonstrated that precisely controlled pore size and shapes can be easily fabricated using a simple, computer-aided process and that multi-layered scaffolds with spatially distributed factors in the same layer or across different layers can be efficiently manufactured using this technique.
Abstract: Our ability to create precise, pre-designed, spa- tially patterned biochemical and physical microenviron- ments inside polymer scaffolds could provide a powerful tool in studying progenitor cell behavior and differentiation under biomimetic, three-dimensional (3D) culture condi- tions. We have developed a simple and fast, layer-by-layer microstereolithography system consisting of an ultra-violet light source, a digital micro-mirror masking device, and a conventional computer projector, that allows fabrication of complex internal features along with precise spatial distri- bution of biological factors inside a single scaffold. Photo- crosslinkable poly(ethylene glycol) diacrylates were used as the scaffold material, and murine bone marrow-derived cells were successfully encapsulated or seeded on fibronectin- functionalized scaffolds. Fluorescently-labeled polystyrene microparticles were used to show the capability of this sys- tem to create scaffolds with complex internal architectures and spatial patterns. We demonstrate that precisely con- trolled pore size and shapes can be easily fabricated using a simple, computer-aided process. Our results further indicate that multi-layered scaffolds with spatially distributed fac- tors in the same layer or across different layers can be efficiently manufactured using this technique. These micro- fabricated scaffolds are conducive for osteogenic differenti- ation of marrow-derived stem cells, as indicated by efficient matrix mineralization. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res 77A: 396 - 405, 2006
341 citations
"Optimization of laser machining pro..." refers background in this paper
...Therefore, a high-throughput process for fabricating hard masks more amenable to any MEMS research laboratory setup is needed for the easier control on the mask-making processes.(3,4) Nonconventional machining processes have been repeatedly used in micromanufacturing, although their application to mask making has not previously been explored....
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TL;DR: In this paper, a detailed description of deep X-ray lithography and an overview of the variety of microstructure products fabricated using the LIGA technique has been presented, including sensors, actuators, micromechanical components, microoptical systems, electrical and optical microconnectors.
218 citations
"Optimization of laser machining pro..." refers methods in this paper
...The laser machining parameters are fully optimized using the design of experiment technique in which a central composite design is used to fit a model by least square techniques.(11) An optimum solution is extracted from the different machining parameters, including energy, pulse frequency, pulse duration, and number of pulses, etc....
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TL;DR: In this paper, the design for an ultraprecision machine tool is introduced by describing its key machine elements and machine tool design procedures, and the focus is on the review and assessment of the state-of-the-art ultra-recision machining tools.
150 citations
"Optimization of laser machining pro..." refers methods in this paper
...With the burgeoning demand of microtechnology, a growing number of industrial applications requiring submicrometer features in various materials have become the need of the day.(1) To fabricate these features, a multistep hybrid machining technique combining laser machining and an existing...
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TL;DR: X-ray LIGA (Lithography, Electrogrowth, Moulding) is one of today's key technologies in microfabrication and upcoming modern (meso)-nano fabrication, already used and anticipated for micromechanics (micromotors, microsensors, spinnerets, etc.), micro-optics, micro-hydrodynamics (fluidic devices), microbiology, in medicine, in biology, and in chemistry for microchemical reactors.
96 citations
TL;DR: In this article, two biodegradable polymeric materials, poly-D-lactic acid (PDLA) and polymer poly-vinyl alcohol (PVA), were micropatterned by ultraviolet lasers.
Abstract: Laser direct writing and percussion-drilling techniques are employed to fabricate two biodegradable micro-devices for biomedical engineering applications. Biodegradable polymeric material, poly-D-lactic acid (PDLA), and polymer poly-vinyl alcohol (PVA) were micropatterned by ultraviolet lasers. The morphology, dimensional accuracy, and surface conditions of the fabricated micro-devices after the laser ablation were studied using a scanning electron microscope (SEM) and a surface profilometer. The experimental results for producing micro-devices are reported. This work on laser micromachining of a biodegradable polymer for applications in biomedical engineering is the first of its kind and demonstrated that this technique is well suited to produce biodegradable microdevices with minimum thermal damage to the surrounding material.
69 citations