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Electronics, Electronique, Mechanical engineering, Génie mécanique, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Generalites, General, Instruments, appareillage, composants et techniques communs à plusieurs branches de la physique et de l'astronomie, Instruments, apparatus, components and techniques common to several branches of physics and astronomy, Techniques, équipements et instruments mécaniques, Mechanical instruments, equipment and techniques, Systèmes et dispositifs micromécaniques, Micromechanical devices and systems, Dimension, Dimensions, Dispositif microélectromécanique, Microelectromechanical device, Dispositivo microelectromecánico, Hydrodynamique, Hydrodynamics, Lithographie sans masque, Maskless lithography, Litografía sin máscara, Microfluidique, Microfluidics, Microstructure, Optimisation, Optimization, Photorésist, Photoresists, Prototypage rapide, Rapid prototyping, and Prototipificación rápida

This paper describes maskless lithography as a rapid and cost-effective technique for fabricating high-quality microfluidic devices in laboratories. The detailed effects of exposure parameters on microstructure features are explored. A quantitative analysis of these effects provides insights into the device design and the selection of optimum processing parameters. To overcome the limitation of small exposure area, subregion stitching and sequential exposure are adopted for fabricating larger patterns. Seamless stitching between adjacent exposure subregions is achieved by optimizing the grayscale values of the stitching side/corner. These data are also valuable for exploring grayscale and multi-step lithography. Various hydrodynamic microdevices are then fabricated and characterized to validate the optimized parameters.

Electronics, Electronique, Mechanical engineering, Génie mécanique, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Generalites, General, Instruments, appareillage, composants et techniques communs à plusieurs branches de la physique et de l'astronomie, Instruments, apparatus, components and techniques common to several branches of physics and astronomy, Techniques, équipements et instruments mécaniques, Mechanical instruments, equipment and techniques, Systèmes et dispositifs micromécaniques, Micromechanical devices and systems, Domaines classiques de la physique (y compris les applications), Fundamental areas of phenomenology (including applications), Mécanique des fluides, Fluid dynamics, Mécanique des fluides appliquée, Applied fluid mechanics, Fluidique, Fluidics, Sciences appliquees, Applied sciences, Industrie des polymeres, peintures, bois, Polymer industry, paints, wood, Technologie des polymères, Technology of polymers, Appareillage et mise en oeuvre, Machinery and processing, Matières plastiques, Plastics, Moulage, Moulding, Genie mecanique. Construction mecanique, Mechanical engineering. Machine design, Mécanique de précision. Horlogerie, Precision engineering, watch making, Composé hydrophobe, Hydrophobic compound, Compuesto hidrofobo, Epoxyde résine, Epoxy resin, Epóxido resina, Fluidique, Fluidics, Formage à chaud, Hot forming, Termoconformado, Gaufrage, Embossing, Gofrado, Gravure faisceau ionique, Ion beam etching, Grabado haz iónico, Gravure ionique réactive, Reactive ion etching, Grabado iónico reactivo, Microfluidique, Microfluidics, Moulage injection, Injection molding, Moldeo por inyección, Méthacrylate de méthyle polymère, PMMA, Outillage, Tooling, Herramienta, Photorésist, Photoresists, Prototypage rapide, Rapid prototyping, Prototipificación rápida, Salle blanche, Clean rooms, Siloxane(diméthyl) polymère, Dimethylsiloxane polymer, Siloxano(dimetil) polímero, Traitement surface, Surface treatments, Microusinage surface, Surface micromachining, and Micromaquinado superficie

We present a novel, cost-efficient process chain for fast tooling and small-lot replication of high-quality, multi-scale microfluidic polymer chips within less than 5 days. The fabrication chain starts with a primary master which is made by well-established cleanroom processes such as DRIE or negative SU-8 resist based surface micromachining. The formation of undercuts in the master which would complicate demolding is carefully avoided. Secondary PDMS masters or epoxy-based masters which are more suitable for common polymer replication schemes such as soft-embossing, hot-embossing or injection molding are subsequently cast from the primary masters. The polymer replica are mainly made of COC and show excellent fidelity with the conventionally micromachined master while displaying no degeneration, even after more than 200 cycles. The use of other polymers such as PMMA is also possible. The process chain further includes surface modification techniques for overall, long-term stable hydrophilic coatings and for local hydrophobic patches as well as a durable sealing based on thermal bonding.

Electronics, Electronique, Mechanical engineering, Génie mécanique, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Domaines classiques de la physique (y compris les applications), Fundamental areas of phenomenology (including applications), Mécanique des fluides, Fluid dynamics, Mécanique des fluides appliquée, Applied fluid mechanics, Fluidique, Fluidics, Sciences appliquees, Applied sciences, Genie mecanique. Construction mecanique, Mechanical engineering. Machine design, Mécanique de précision. Horlogerie, Precision engineering, watch making, Electroosmose, Electroosmosis, Electro-osmosis, Etude expérimentale, Experimental study, Estudio experimental, Fluidique, Fluidics, Fluídico, Miniaturisation, Miniaturization, Miniaturización, Mécanique précision, Precision engineering, Mecánica precisión, Photofabrication, Fotofabricación, Photolithographie, Photolithography, Fotolitografía, Photorésist, Photoresist, Fotorresistente, Processus fabrication, Production process, Proceso fabricación, Prototypage rapide, Rapid prototyping, Prototipificación rápida, Siloxane(diméthyl) polymère, Dimethylsiloxane polymer, Siloxano(dimetil) polímero, Solution aqueuse, Aqueous solution, and Solución acuosa

This paper describes a procedure for rapidly and conveniently prototyping microfluidic devices that are useful with aqueous solutions. A design (with diameters of channels ≥20 μm) is created in a computer-aided design program and printed at high resolution on a transparency. This transparency is used as a mask in photolithography to create a master in positive relief photoresist: casting poly(dimethyl siloxane) (PDMS) against this master yields a polymeric replica containing a network of bas-relief channels. The channels are closed and sealed irreversibly by oxidizing the replica and another flat substrate (PDMS, glass, silicon, silicon oxide) in an oxygen plasma and bringing the two surfaces into conformal contact. Oxidation of the polymer allows the formation of a seal without using adhesives; it also generates channels that support electro-osmotic flow (EOF) and fill easily with aqueous solutions. Two microfluidic devices-a fluidic switch and a side channel flow controller-have been fabricated using this rapid prototyping methodology. These devices were tested using aqueous solutions as the test fluid and actuated by EOF.

Electronics, Electronique, Mechanical engineering, Génie mécanique, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Domaines classiques de la physique (y compris les applications), Fundamental areas of phenomenology (including applications), Mécanique des fluides, Fluid dynamics, Mécanique des fluides appliquée, Applied fluid mechanics, Fluidique, Fluidics, Sciences appliquees, Applied sciences, Electronique, Electronics, Electronique des semiconducteurs. Microélectronique. Optoélectronique. Dispositifs à l'état solide, Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices, Fabrication microélectronique (technologie des matériaux et des surfaces), Microelectronic fabrication (materials and surfaces technology), Lithography, masks and pattern transfer, Attaque chimique, Chemical etching, Ataque químico, Couche mince, Thin film, Capa fina, Echantillonnage, Sampling, Muestreo, Etude expérimentale, Experimental study, Estudio experimental, Joint étanchéité, Seal, Soldadura estanqueidad, Masque photographique, Photographic mask, Máscara fotográfica, Microfluide, Microfluid, Microfluido, Micromanipulation, Micromanipulación, Mécanique précision, Precision engineering, Mecánica precisión, Métrologie surface, Surface metrology, Metrología superficie, Photorésist, Photoresist, Fotorresistencia, Processus fabrication, Production process, Proceso fabricación, Profilométrie, Profilometry, Perfilometría, Prototype, Prototipo, Puce électronique, Chip, Pulga electrónica, Rugosité, Roughness, Rugosidad, Substrat, Substrate, Substrato, Verre sodocalcique, and Soda-lime glasses

This paper describes a fast, low-cost but reliable process for the fabrication of microfluidic systems on soda-lime glass substrates. Instead of using an expensive metal or polisilicon/nitride layer as an etch mask, a thin layer of AZ 4620 positive photoresist (PR) is used for buffered oxide etching (BOE) of soda-lime glass. A novel two-step baking process prolongs the survival time of the PR mask in the etchant, which avoids serious peeling problems of the PR. A new process to remove precipitated particles generated during the etching process is also reported in which the glass substrate is dipped into a 1 M hydrochloride solution. A microfluidic channel with a depth of 35.95 ± 0.39 μm is formed after 40 min BOE in an ultrasonic bath. The resulting channel has a smooth profile with a surface roughness of less than 45.95 ± 7.96 Å. Glass chips with microfluidic channels are then bonded at 580 °C for 20 min to seal the channel while a slight pressure is applied. A new bonding process has been developed such that the whole process can be finished within 10 h. To our knowledge, this is the shortest processing time that has ever been reported. In the present study, an innovative microfluidic device, a 'micro flow-through sampling chip', has been demonstrated using the fabrication method. Successful sampling and separation of Cy5-labelled bovine serum albumin (BSA) and anti-BSA has been achieved. This simple fabrication process is suitable for fast prototyping and mass production of microfluidic systems.

Electronics, Electronique, Mechanical engineering, Génie mécanique, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Generalites, General, Instruments, appareillage, composants et techniques communs à plusieurs branches de la physique et de l'astronomie, Instruments, apparatus, components and techniques common to several branches of physics and astronomy, Techniques, équipements et instruments mécaniques, Mechanical instruments, equipment and techniques, Systèmes et dispositifs micromécaniques, Micromechanical devices and systems, Sciences appliquees, Applied sciences, Electronique, Electronics, Electronique des semiconducteurs. Microélectronique. Optoélectronique. Dispositifs à l'état solide, Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices, Fabrication microélectronique (technologie des matériaux et des surfaces), Microelectronic fabrication (materials and surfaces technology), Genie mecanique. Construction mecanique, Mechanical engineering. Machine design, Mécanique de précision. Horlogerie, Precision engineering, watch making, Angle contact, Contact angle, Angulo contacto, Composé hydrophobe, Hydrophobic compound, Compuesto hidrofobo, Contact dynamique, Dynamic contact, Contacto dinámico, Epoxyde résine, Epoxy resin, Epóxido resina, Etude expérimentale, Experimental study, Estudio experimental, Formation motif, Patterning, Formacíon motivo, Modélisation, Modeling, Modelización, Mouillage, Wetting, Remojo, Photorésist, Photoresist, Fotorresistencia, Régime statique, Static conditions, Régimen estático, Résist, Resist, Resistencia, 0710C, 8540H, Microstructure élancée, High aspect ratio microstructure HARM, and Microestructura esbelta

In this work we present a reliable technique for the production of large areas of high aspect-ratio patterns and describe their use as model super-hydrophobic systems. The high thickness and straight sidewalls possible with SU-8 were used to generate dense patterns of small pillars. These photoresist patterns could be used directly, without the need for micromoulding. A method is given allowing resist thickness to be varied over a wide range and a bottom antireflective layer was used to simplify patterning on reflective substrates. This patterning technique allows rapid testing of wetting theories, as pattern size and depth can be varied simply and samples can be produced in sufficient numbers for laboratory use. We show how the static contact angle of water varies with pattern height for one sample-pattern and how static and dynamic contact angles vary with dimension using high aspect-ratio patterns.

Electronics, Electronique, Mechanical engineering, Génie mécanique, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Generalites, General, Instruments, appareillage, composants et techniques communs à plusieurs branches de la physique et de l'astronomie, Instruments, apparatus, components and techniques common to several branches of physics and astronomy, Techniques, équipements et instruments mécaniques, Mechanical instruments, equipment and techniques, Systèmes et dispositifs micromécaniques, Micromechanical devices and systems, Domaines classiques de la physique (y compris les applications), Fundamental areas of phenomenology (including applications), Mécanique des fluides, Fluid dynamics, Mécanique des fluides appliquée, Applied fluid mechanics, Fluidique, Fluidics, Sciences appliquees, Applied sciences, Industrie des polymeres, peintures, bois, Polymer industry, paints, wood, Technologie des polymères, Technology of polymers, Appareillage et mise en oeuvre, Machinery and processing, Matières plastiques, Plastics, Moulage, Moulding, Genie mecanique. Construction mecanique, Mechanical engineering. Machine design, Mécanique de précision. Horlogerie, Precision engineering, watch making, Epoxyde résine, Epoxy resin, Epóxido resina, Fluidique, Fluidics, Force adhérence, Adhesive strength, Fuerza adherencia, Hydrocarbure fluoré, Fluorocarbon, Hidrocarburo fluorado, Mesure électrique, Electrical measurement, Medida eléctrica, Moulage injection, Injection molding, Moldeo por inyección, Moule, Mold, Molde, Nickel, Oléfine copolymère, Olefin copolymer, Olefina copolímero, Oxyde de silicium, Silicon oxides, Photorésist, Photoresists, Rupture, Ruptures, Résistance rupture, Rupture strength, Resistencia ruptura, Spectrométrie, Spectroscopy, Système sur puce, System on a chip, Microfluidique, Microfluidics, and Microfluídico

We present fast prototyping of injection molding tools by the definition of microfluidic structures in a light-curable epoxy (SU-8) directly on planar nickel mold inserts. Optimized prototype mold structures could withstand injection molding of more than 300 replicas in cyclic olefin copolymer (COC) without any signs of failure or release. The key parameters to avoid mold failure are maximum adhesion strength of the epoxy to the nickel insert and minimum interfacial energy of the epoxy pattern to the molded polymer. Optimal molding of microstructures with vertical sidewalls was found for nickel inserts pre-coated by silicon oxide before applying the structured epoxy, followed by coating of the epoxy by a fluorocarbon layer prior to injection molding. Further improvements in the mold stability were observed after homogeneous coating of the patterned epoxy by a second reflowed layer of epoxy, likely due to the resulting reduction in sidewall steepness. We employed the latter method for injection molding bondable polymer microfluidic chips with integrated conducting polymer electrode arrays that permitted the culture and on-chip analysis of cell spreading by impedance spectroscopy.

Electronics, Electronique, Mechanical engineering, Génie mécanique, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Generalites, General, Instruments, appareillage, composants et techniques communs à plusieurs branches de la physique et de l'astronomie, Instruments, apparatus, components and techniques common to several branches of physics and astronomy, Techniques, équipements et instruments mécaniques, Mechanical instruments, equipment and techniques, Systèmes et dispositifs micromécaniques, Micromechanical devices and systems, Domaines classiques de la physique (y compris les applications), Fundamental areas of phenomenology (including applications), Mécanique des fluides, Fluid dynamics, Mécanique des fluides appliquée, Applied fluid mechanics, Fluidique, Fluidics, Sciences appliquees, Applied sciences, Electronique, Electronics, Electronique des semiconducteurs. Microélectronique. Optoélectronique. Dispositifs à l'état solide, Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices, Fabrication microélectronique (technologie des matériaux et des surfaces), Microelectronic fabrication (materials and surfaces technology), Genie mecanique. Construction mecanique, Mechanical engineering. Machine design, Mécanique de précision. Horlogerie, Precision engineering, watch making, Fluidique, Fluidics, Fluídico, Gradient, Gradiente, Gravure faisceau ionique, Ion beam etching, Grabado haz iónico, Gravure ionique réactive, Reactive ion etching, Grabado iónico reactivo, Liquide, Liquid, Líquido, Lithographie, Lithography, Litografía, Microfluidique, Microfluidics, Photorésist, Photoresist, Fotorresistencia, Processus fabrication, Production process, and Proceso fabricación

Etertec HQ-6100 dry film photoresist was used in this work to fabricate soft-lithography masters applied to microfluidic applications. We demonstrated that the use of this photoresist was a convenient alternative to conventional microfabrication approaches based on DRIE and liquid photoresists for fast-prototyping of microfluidic structures. Our method was at least two times faster than conventional processes and required limited investment for equipments. Finally, this approach was applied to the design and fabrication of microfluidic networks used for gradient generation in bulk solution.

Electronics, Electronique, Mechanical engineering, Génie mécanique, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Genie mecanique. Construction mecanique, Mechanical engineering. Machine design, Mécanique de précision. Horlogerie, Precision engineering, watch making, Cire, Wax, Cera, Liaison matériau, Bonding, Lithographie, Lithography, Litografía, Mode opératoire, Operating mode, Método operatorio, Mécanique précision, Precision engineering, Mecánica precisión, Photorésist, Photoresist, Fotorresistencia, Prototypage rapide, Rapid prototyping, Prototipificación rápida, Refusion, Remelting, and Refusión

Here we present facile microfabrication processes, referred to as print-to-pattern dry film photoresist (DFP) lithography, that utilize the combined advantages of wax printing and DFP to produce micropatterned substrates with high resolution over a large surface area in a non-cleanroom setting. The print-to-pattern methods can be performed in an out-of-cleanroom environment making microfabrication much more accessible to minimally equipped laboratories. Two different approaches employing either wax photomasks or wax etchmasks from a solid ink desktop printer have been demonstrated that allow the DFP to be processed in a negative tone or positive tone fashion, respectively, with resolutions of 100 μm. The effect of wax melting on resolution and as a bonding material was also characterized. In addition, solid ink printers have the capacity to pattern large areas with high resolution, which was demonstrated by stacking DFP layers in a 50 mm x 50 mm woven pattern with 1 mm features. By using an office printer to generate the masking patterns, the mask designs can be easily altered in a graphic user interface to enable rapid prototyping.

Electronics, Electronique, Mechanical engineering, Génie mécanique, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Electronique, Electronics, Electronique des semiconducteurs. Microélectronique. Optoélectronique. Dispositifs à l'état solide, Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices, Dispositifs hyperfréquences et à ondes submillimétriques, dispositifs à transfert d'électrons, Microwave and submillimeter wave devices, electron transfer devices, Décollement épitaxique, Lift off, Desprendimiento epitáxico, Lithographie faisceau électron, Electron beam lithography, Litografía haz electrón, Photorésist, Photoresist, Fotorresistencia, Procédé fabrication, Manufacturing process, Procedimiento fabricación, Prototypage rapide, Rapid prototyping, Prototipificación rápida, Revêtement protecteur, Protective coatings, Revestimiento protector, Styrène dérivé polymère, Styrene derivative polymer, Estireno derivado polímero, Thiophène dérivé polymère, Thiophene derivative polymer, and Tiofeno derivado polímero

Highly sensitive chemically amplified resists are well suited for large-area, high-resolution rapid prototyping by electron beam lithography. The major drawback of these resists is their susceptibility to T-topping effects, sensitivity losses, and linewidth variations caused by delay times between individual process steps. Hence, they require a very tight process control, which hinders their potentially wide application in R&D. We demonstrate a highly robust electron beam lithography lift-off process using a chemically amplified positive tone 40XT photoresist in combination with an acidic conducting polymer (PEDOT:PSS) as a protective top-coating. Even extended delay times of 24h did not lead to any sensitivity losses or linewidth variations. Moreover, an overall high performance with a resolution of 80 nm (after lift-off) and a high sensitivity (<10 μC/cm2) comparable to other standard chemically amplified resists was achieved. The development characteristics of this resist-layer system revealed new insights into the immanent trade-off between resolution and process stability.

Electronics, Electronique, Mechanical engineering, Génie mécanique, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Genie mecanique. Construction mecanique, Mechanical engineering. Machine design, Mécanique de précision. Horlogerie, Precision engineering, watch making, Mécanique fluide, Fluid mechanics, Mecánica flúido, Biocompatibilité, Biocompatibility, Biocompatibilidad, Microfluidique, Microfluidics, Microfluidic, Mécanique précision, Precision engineering, Mecánica precisión, Mélangeur, Mixer, Mezclador, Photorésist, Photoresist, Fotorresistencia, Prototypage rapide, Rapid prototyping, Prototipificación rápida, Siloxane(diméthyl) polymère, Dimethylsiloxane polymer, Siloxano(dimetil) polímero, Soupape, Valve, Válvula, Système acquisition donnée, Data acquisition system, Sistema adquisición dato, Système sur puce, System on a chip, Sistema sobre pastilla, Lithographie douce, Soft lithography, and Litografía blanda

Multilayer soft lithography has become a powerful tool in analytical chemistry, biochemistry, material and life sciences, and medical research. Complex fluidic micro-circuits require reliable components that integrate easily into microchips. We introduce two novel approaches to master mold fabrication for constructing in-line micro-valves using SU-8. Our fabrication techniques enable robust and versatile integration of many lab-on-a-chip functions including filters, mixers, pumps, stream focusing and cell-culture chambers, with in-line valves. SU-8 created more robust valve master molds than the conventional positive photoresists used in multilayer soft lithography, but maintained the advantages of biocompatibility and rapid prototyping. As an example, we used valve master molds made of SU-8 to fabricate PDMS chips capable of precisely controlling beads or cells in solution.

Electronics, Electronique, Mechanical engineering, Génie mécanique, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Generalites, General, Instruments, appareillage, composants et techniques communs à plusieurs branches de la physique et de l'astronomie, Instruments, apparatus, components and techniques common to several branches of physics and astronomy, Techniques, équipements et instruments mécaniques, Mechanical instruments, equipment and techniques, Systèmes et dispositifs micromécaniques, Micromechanical devices and systems, Domaines classiques de la physique (y compris les applications), Fundamental areas of phenomenology (including applications), Mécanique des fluides, Fluid dynamics, Mécanique des fluides appliquée, Applied fluid mechanics, Fluidique, Fluidics, Sciences appliquees, Applied sciences, Electronique, Electronics, Electronique des semiconducteurs. Microélectronique. Optoélectronique. Dispositifs à l'état solide, Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices, Fabrication microélectronique (technologie des matériaux et des surfaces), Microelectronic fabrication (materials and surfaces technology), Genie mecanique. Construction mecanique, Mechanical engineering. Machine design, Mécanique de précision. Horlogerie, Precision engineering, watch making, Adhérence, Adhesion, Dispensation médicament, Drug dispensation, Dispensación medicamento, Décollement épitaxique, Lift off, Desprendimiento epitáxico, Epoxyde résine, Epoxy resin, Epóxido resina, Etude expérimentale, Experimental study, Fluidique, Fluidics, Gouttelette, Droplets, Mesure, Metering, Microfluidique, Microfluidics, Microscopie électronique balayage, Scanning electron microscopy, Photorésist, Photoresists, Prototypage rapide, Rapid prototyping, Prototipificación rápida, Reproductibilité, Reproducibility, Reproductividad, Retrait, Shrinkage, Système contrôle commande, Command and control systems, 0710C, and 8540H

This paper reports on a novel multilayer SU-8 lift-off technology which allows for low cost rapid prototyping of microfluidic devices. The process presented is based on a multi-layer structure of SU-8 which can be released from the substrate after processing and enables the creation of through holes. The lift-off is accomplished during the development by making use of the volume shrinkage of the SU-8 during postbaking and by modification of the adhesion to the substrate. To demonstrate the technology, prototypes of a multichannel microdispenser according to the Dispensing Well Plate (DWP) principle (Koltay et al 2004 Sensors Actuators A 116 472, 483) were fabricated. The samples contain 24 parallel dispensing units with 100 μm through holes and a dosage volume of 60 nl. For the first time all functional structures such as reservoirs, channels and through holes (nozzles) of the DWP were realized exclusively in the photodefinable epoxy SU-8. To assess the quality of the SU-8 process the geometry of the presented prototypes is characterized by profiler measurements and scanning electron microscopy. Furthermore, the dispensing performance is studied experimentally by gravimetrical measurements. A reproducibility of the dosage volume of 1% and a homogeneity within individual droplet arrays of 3.6% were achieved.

Electronics, Electronique, Mechanical engineering, Génie mécanique, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Generalites, General, Instruments, appareillage, composants et techniques communs à plusieurs branches de la physique et de l'astronomie, Instruments, apparatus, components and techniques common to several branches of physics and astronomy, Techniques, équipements et instruments mécaniques, Mechanical instruments, equipment and techniques, Systèmes et dispositifs micromécaniques, Micromechanical devices and systems, Domaines classiques de la physique (y compris les applications), Fundamental areas of phenomenology (including applications), Mécanique des fluides, Fluid dynamics, Mécanique des fluides appliquée, Applied fluid mechanics, Fluidique, Fluidics, Sciences appliquees, Applied sciences, Electronique, Electronics, Electronique des semiconducteurs. Microélectronique. Optoélectronique. Dispositifs à l'état solide, Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices, Fabrication microélectronique (technologie des matériaux et des surfaces), Microelectronic fabrication (materials and surfaces technology), Genie mecanique. Construction mecanique, Mechanical engineering. Machine design, Mécanique de précision. Horlogerie, Precision engineering, watch making, Dispositif microélectromécanique, Microelectromechanical device, Dispositivo microelectromecánico, Défaut forme, Form defect, Defecto forma, Ecoulement conduite, Pipe flow, Ecoulement liquide, Liquid flow, Effet optothermique, Optothermal effect, Efecto optotérmico, Etat surface, Surface states, Fluidique, Fluidics, Microfluidique, Microfluidics, Modélisation, Modelling, Méthacrylate de méthyle polymère, PMMA, Photorésist, Photoresists, Prototypage rapide, Rapid prototyping, Prototipificación rápida, Siloxane(diméthyl) polymère, Dimethylsiloxane polymer, Siloxano(dimetil) polímero, Surface lisse, Smooth surface, Superficie lisa, Usinage laser, and Laser beam machining

This paper reports a novel approach to eliminate the bulges formed at the rim of a channel in a PMMA polymer substrate during CO2 laser micromachining by covering a PDMS or JSR photoresist layer on the polymer substrate to get a good quality of smooth surface for the MEMS application. The bulges formed in the conventional laser micromachined polymer result in problems of bonding of the microfluidic chips or the clogging of liquid flow in the channel. Different cover layers of PDMS material and JSR photoresist unexposed or exposed by UV light were used to study the phenomena of formation and elimination of bulges. Also, a different number of passes were performed to investigate the variation of bulge shape and its formation mechanism as well as the profile of the channel. A physical model for the bulge formation during CO2 laser micromachining based on the photothermal melting mechanism was proposed. The micromachined PMMA polymer without bulges at the rim of the channel has been demonstrated using a cover layer on the substrate by the CO2 laser technology at low cost and rapid prototyping.

Electronics, Electronique, Mechanical engineering, Génie mécanique, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Domaines classiques de la physique (y compris les applications), Fundamental areas of phenomenology (including applications), Mécanique des fluides, Fluid dynamics, Mécanique des fluides appliquée, Applied fluid mechanics, Fluidique, Fluidics, Sciences biologiques et medicales, Biological and medical sciences, Sciences biologiques fondamentales et appliquees. Psychologie, Fundamental and applied biological sciences. Psychology, Biotechnologie, Biotechnology, Méthodes. Procédés. Technologies, Methods. Procedures. Technologies, Techniques d'immobilisation, Immobilization techniques, Immobilisation de cellules entières et d'organites cellulaires, Immobilization of organelles and whole cells, Epoxyde résine, Epoxy resin, Epóxido resina, Gouttelette, Droplets, Hydrodynamique, Hydrodynamics, Lithographie, Lithography, Microencapsulation, Microencapsulación, Nanofluidique, Nanofluidics, Nanofluídico, Photofabrication, Fotofabricación, Photolithographie, Photolithography, Photorésist, Photoresists, Prototypage rapide, Rapid prototyping, Prototipificación rápida, Stéréolithographie, Stereolithography, Stereolitografia, Traitement surface, Surface treatments, Microfluidique, Microfluidics, and Microfluídico

A combination of photolithography and stereolithography was successfully used to fabricate a hybrid axisymmetric flow-focusing device (h-AFFD) that produces monodisperse picoliter droplets. The h-AFFD achieved the same level of hydrodynamic performance as a monolithic AFFD produced by only stereolithography from acrylic resin. Since the h-AFFD had a narrower orifice (50 or 100 μm in diameter), created in an SU-8 sheet by photolithography, than the monolithic AFFD, we were able to produce picoliter droplets. We also succeeded in producing monodisperse droplets encapsulating a single cell without any surface modification. (Some figures in this article are in colour only in the electronic version).

Electronics, Electronique, Mechanical engineering, Génie mécanique, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Domaines classiques de la physique (y compris les applications), Fundamental areas of phenomenology (including applications), Mécanique des fluides, Fluid dynamics, Mécanique des fluides appliquée, Applied fluid mechanics, Fluidique, Fluidics, Sciences appliquees, Applied sciences, Electronique, Electronics, Electronique des semiconducteurs. Microélectronique. Optoélectronique. Dispositifs à l'état solide, Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices, Fabrication microélectronique (technologie des matériaux et des surfaces), Microelectronic fabrication (materials and surfaces technology), Physicochimie des polymeres, Physicochemistry of polymers, Polymères organiques, Organic polymers, Préparation, cinétique, thermodynamique, mécanisme et catalyseurs, Preparation, kinetics, thermodynamics, mechanism and catalysts, Polymérisation, Polymerization, Genie mecanique. Construction mecanique, Mechanical engineering. Machine design, Mécanique de précision. Horlogerie, Precision engineering, watch making, Ablation, Absorption 2 photons, Two photon absorption, Absorción 2 fotones, Lithographie sans masque, Maskless lithography, Litografía sin máscara, Photorésist, Photoresists, Polymérisation, Polymerization, Processus 2 photons, Two-photon processes, Propriété chimique, Chemical properties, Prototypage rapide, Rapid prototyping, Prototipificación rápida, Seuil, Threshold, Umbral, Microfluidique, Microfluidics, and Microfluídico

Two-photon absorption (TPA) polymerization assisted ablation is a simple, fast and repeatable method for fabricating micro-fluidic channels. Since it is a maskless method, it is relatively inexpensive and faster than other conventional lithography techniques. Unlike direct ablation, TPA assisted ablation requires significantly less energy; as a result, it has greater control over the desired feature size and spatial resolution. In this work, we also show that ORMOCER has pronounced TPA assisted ablation threshold behavior, which is related to laser parameters such as spot radius, repetition rate and scan speed, in addition to the chemical properties of the photoresist. By manipulating these parameters, any two-dimensional-shaped micro-fluidic channels with desired channel width and depth can be fabricated.