Femtosecond micro- and nano-machining of materials for microfluidic applications

White, Yelena; Parrish, Matthew; Li, Xiaoxuan; Davis, Lloyd M.; Hofmeister, William

doi:10.1117/12.799855

Cited by 13 publications

(6 citation statements)

References 23 publications

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“…fs pulses have been widely employed in micromachining bulk polymers, including PMMA and PDMS. This technique has been successfully employed in PMMA to engineer and integrate various optical/photonic and microfluidic structures, such as volume optical data storage [11][12][13][14], 2D and 3D gratings [15][16][17][18][19][20][21][22], waveguides [23][24][25][26], photonic band gap structures [27][28][29], microfluidic structures/devices [30][31][32][33][34], and structures for MEMS applications [35]. However, the interaction of laser pulses, particularly ultrashort pulses, with polymers is intricate and requires several complementary techniques to discover the changes occurring on the surface or inside the bulk [36][37][38][39][40][41][42][43][44][45][46][47].…”

Section: Introductionmentioning

confidence: 99%

Fabrication and optical characterization of microstructures in poly(methylmethacrylate) and poly(dimethylsiloxane) using femtosecond pulses for photonic and microfluidic applications

2010

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We fabricated several microstructures, such as buried gratings, surface gratings, surface microcraters, and microchannels, in bulk poly(methylmethacrylate) (PMMA) and poly(dimethylsiloxane) (PDMS) using the femtosecond (fs) direct writing technique. A methodical study of the diffraction efficiency (DE) of the achieved gratings was performed as a function of scanning speed, energy, and focal spot size in both PMMA and PDMS. An optimized set of writing parameters has been identified for achieving efficient gratings in both cases. The highest DE recorded in a PDMS grating was ∼10% and ∼34% in a PMMA grating obtained with an 0:65 NA (40X) objective with a single scan. Spectroscopic techniques, including Raman, UV-visible, electron spin resonance (ESR), and physical techniques, such as laser confocal and scanning electron microscopy (SEM), were employed to examine the fs laser-modified regions in an attempt to understand the mechanism responsible for physical changes at the focal volume. Raman spectra collected from the modified regions of PMMA indicated bond softening or stress-related mechanisms responsible for structural changes. We have also observed emission from the fs-modified regions of PMMA and PDMS. An ESR spectrum, recorded a few days after irradiation, from the fs laser-modified regions in PMMA did not reveal any signature of free radicals. However, fs-modified PDMS regions exhibited a single peak in the ESR signal. The probable rationale for the behavior of the ESR spectra in PMMA and PDMS are discussed in the light of free radical formation after fs irradiation. Microchannels within the bulk and surface of PMMA were achieved as well. Microcraters on the surfaces of PMMA and PDMS were also accomplished, and the variation of structure properties with diverse writing conditions has been studied.

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Section: Introductionmentioning

confidence: 99%

Fabrication and optical characterization of microstructures in poly(methylmethacrylate) and poly(dimethylsiloxane) using femtosecond pulses for photonic and microfluidic applications

2010

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“…• covering of modified surface by the products of this modification, or • by the phase transition of surface layer to graphite-like structure [14,20], which is affected by the heating of the surface as a result of a rapid return to the same modified place of laser during rescanning of the surface. A high scan speed increases surface temperature, while a low speed allows for better heat transfer from the modified place-lower surface temperature.…”

Section: Resultsmentioning

confidence: 99%

“…A great possibility of the laser modification of diamond surface is the micromachining of three-dimensional structures, which can help in the development of diamond-based photonic devices and shows the perspectives in the field of Microelectromechanical Systems (MEMS), microfluidics and biophysics [9,14]. The analysis of the nanoablation process of diamond indicates that the photoreaction occurs directly between the surface-layer atoms and adsorbed molecules-one atomic layer of material (a = 0.178 nm-the average interatomic distance in the diamond lattice) is generally removed by photoetching during a pulse [10,13].…”

Section: Introductionmentioning

confidence: 99%

Microstructures Manufactured in Diamond by Use of Laser Micromachining

et al. 2020

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Different microstructures were created on the surface of a polycrystalline diamond plate (obtained by microwave plasma-enhanced chemical vapor deposition—MW PECVD process) by use of a nanosecond pulsed DPSS (diode pumped solid state) laser with a 355 nm wavelength and a galvanometer scanning system. Different average powers (5 to 11 W), scanning speeds (50 to 400 mm/s) and scan line spacings (“hatch spacing”) (5 to 20 µm) were applied. The microstructures were then examined using scanning electron microscopy, confocal microscopy and Raman spectroscopy techniques. Microstructures exhibiting excellent geometry were obtained. The precise geometries of the microstructures, exhibiting good perpendicularity, deep channels and smooth surfaces show that the laser microprocessing can be applied in manufacturing diamond microfluidic devices. Raman spectra show small differences depending on the process parameters used. In some cases, the diamond band (at 1332 cm−1) after laser modification of material is only slightly wider and shifted, but with no additional peaks, indicating that the diamond is almost not changed after laser interaction. Some parameters did show that the modification of material had occurred and additional peaks in Raman spectra (typical for low-quality chemical vapor deposition CVD diamond) appeared, indicating the growing disorder of material or manufacturing of the new carbon phase.

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“…These problems can be reduced by cleaning the ablated area immediately after the ablation. This cleaning process maybe will increase the processing time of the laser micromachining [16][17][18][19][20]. At the same time, the laser micromachining process needs to be carried out in stable condition and avoid firing of the debris or residue.…”

Section: Resultsmentioning

confidence: 99%

Process development and characterization towards microstructural realization using laser micromachining for MEMS

et al. 2020

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This paper presents the process development and characterization towards microstructural realization using laser micromachining for MEMS. Laser micromachining technique is environmental friendly, fast patterning and able to avoid multi steps in conventional lithography based microfabrication techniques. This research focuses on understanding the dimensional properties of materials of the laser beam on the silicon wafers where microstructures were fabricated. Four main parameters like rectangular variable aperture (RVA-XY) size, number of pulse, stage/table feed rate and laser energy play important role in laser ablation process. The pattern of the microchannel or line with 1 cm length was drawn by AutoCAD software or any CAD software. The pattern in the CAD software is then transferred onto the silicon wafer by using laser micromachining. Finally, high power microscope (HPM) and Stylus Profiler will be used as measurement tools for observing and analysing the width and depth of the microchannel structures fabricated by laser micromachining. When using bigger size of RVA, it will lead to bigger microchannel width. There are a little effects or almost comparable in term of microchannel depth if varying all parameters' value. Surface roughness test also needs to be considered before choosing the best setting for the laser ablation.

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Femtosecond micro- and nano-machining of materials for microfluidic applications

Cited by 13 publications

References 23 publications

Fabrication and optical characterization of microstructures in poly(methylmethacrylate) and poly(dimethylsiloxane) using femtosecond pulses for photonic and microfluidic applications

Fabrication and optical characterization of microstructures in poly(methylmethacrylate) and poly(dimethylsiloxane) using femtosecond pulses for photonic and microfluidic applications

Microstructures Manufactured in Diamond by Use of Laser Micromachining

Process development and characterization towards microstructural realization using laser micromachining for MEMS

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