Fabrication of fluidic manifold systems using single-exposure grayscale masks

Hayden, Christopher J.; Burt, Julian P.H.

doi:10.1117/12.425210

Cited by 7 publications

(5 citation statements)

References 5 publications

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“…Excimer laser micromachining is a versatile tool for prototyping light guide structures. Direct write machining processes allow the rapid implementation of design iterations while more advanced machining processes allow variable depth and even 3D contoured guide structures to be produced [7].…”

Section: Light Guidesmentioning

confidence: 99%

Laser micromachining of optical biochips

et al. 2007

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Optical biochips may incorporate both optical and microfluidic components as well as integrated light emitting semiconductor devices. They make use of a wide range of materials including polymers, glasses and thin metal films which are particularly suitable if low cost devices are envisaged. Precision laser micromachining is an ideal flexible manufacturing technique for such materials with the ability to fabricate structures to sub-micron resolutions and a proven track record in manufacturing scale up.Described here is the manufacture of a range of optical biochip devices and components using laser micromachining techniques. The devices employ both microfluidics and electrokinetic processes for biological cell manipulation and characterization. Excimer laser micromachining has been used to create complex microelectrode arrays and microfluidic channels. Excimer lasers have also been employed to create on-chip optical components such as microlenses and waveguides to allow integrated vertical and edge emitting LEDs and lasers to deliver light to analysis sites within the biochips.Ultra short pulse lasers have been used to structure wafer level semiconductor light emitting devices. Both surface patterning and bulk machining of these active wafers while maintaining functionality has been demonstrated. Described here is the use of combinations of ultra short pulse and excimer lasers for the fabrication of structures to provide ring illumination of in-wafer reaction chambers.The laser micromachining processes employed in this work require minimal post-processing and so make them ideally suited to all stages of optical biochip production from development through to small and large volume production.

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Section: Light Guidesmentioning

confidence: 99%

Laser micromachining of optical biochips

et al. 2007

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“…This corresponds to a dimension of 10 µm at the mask, due to the demagnification factor of the lens used. The CDOD algorithm was incorporated into a Matlab R program that was originally developed for photolithographic greyscale mask fabrication [15]. By entering the relevant 3D design of the required microstructure, the modified program generated the appropriate laser greyscale mask pattern.…”

Section: Fabrication Of Greyscale Test Maskmentioning

confidence: 99%

“…Such processes are well suited and optimized for producing planar microstructures in a variety of materials, including ceramics and polymers. However, the demand for non-planar microstructures in MEMs and lab-on-a-chip devices, for example micro-lenses and other micro-optical components [1][2][3][4][5][6][7][8][9][10][11][12][13][14] or contoured micro-fluidic channels [15], requires alternative, non-planar fabrication processes to be developed. Stereolithography has been shown to be a viable, alternative approach for creating 3D structures, although some quantization levels are usually present [16][17][18].…”

Section: Introductionmentioning

confidence: 99%

Three-dimensional excimer laser micromachining using greyscale masks

Hayden

2003

J. Micromech. Microeng.

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Greyscale masks have been successfully implemented in an excimer laser micromachining system to produce structures with a continuous profile. During this work, it was found possible to machine structures to depths of several tens of microns with no observable mask degradation. The greyscale mask transmissions were defined using a matrix of pixels whose dimension was smaller than the resolution limit of the optical system in the laser micromachining system. By reduction-projecting the greyscale mask pattern onto the workpiece, the local fluence at the workpiece could be predetermined and hence the local machining rates controlled. This enabled three-dimensional (3D) structures to be fabricated at the workpiece in a single machining operation. Under the experimental conditions used in this investigation, the rate at which material was ablated was found to depend linearly on the percentage transmission of the mask. Various test structures, including complex 3D-contoured fluidic channels, have been produced.

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“…The surfaces of micromachined 3D features should have welldefined contours and curvatures for the fabrication of devices such as diffractive or refractive optical elements, microfluidic channel systems, etc. This grayscale photomask technology allows the creation of 3D structures via a low cost, short cycle time, single exposure process [1][2][3][4][5][6]. There are two types of grayscale photomasks: digital and analog.…”

Section: Introductionmentioning

confidence: 99%

Expanding grayscale capability of direct-write grayscale photomask by using modified Bi/In compositions

et al. 2005

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Bimetallic thin films have been proven to be effective in creating analog direct write grayscale photomasks. DC-sputtered Bi/In or Sn/In oxidizes under laser writing exposure. The optical density decreases from >3OD as deposited to a transparency of <0.22OD at 365 nm with increasing laser power. The bimetallic film has a response curve that is nearly linear for much of the curve, but non-linear at maximum absorption and transmission. In order to create more accurate gray levels, a more gradual OD change versus laser writing power is desired. In this research a new reactive sputtered, oxygenated Bi/In film was created that has an 8-bits grayscale level sensitivity of 1.1 gray levels/mV, compared with the previous Bi/In of 3.2 gray levels/mV and Sn/In of 2.8 gray levels/mV. This modified Bi/In film provides more than twice the laser writing power range for controlling the same OD range, as compared to our original Bi/In or Sn/In films. This wider power range provides easier and more accurate laser power-to-grayscale calibration, because each grayscale can now be spaced more evenly over the increased laser writing power range. In addition, the surface of modified Bi/In is found to be much smoother than the original Bi/In and Sn/In films, thus increasing the overall quality of grayscale photomask. Finally grayscale uniformity of the laser writing process has been investigated and techniques such as laser beam shaping and defocusing have been used successfully to eliminate the variations.

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Fabrication of fluidic manifold systems using single-exposure grayscale masks

Cited by 7 publications

References 5 publications

Laser micromachining of optical biochips

Laser micromachining of optical biochips

Three-dimensional excimer laser micromachining using greyscale masks

Expanding grayscale capability of direct-write grayscale photomask by using modified Bi/In compositions

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