Rapid direct writing of high‐aspect‐ratio trenches in silicon

1987 ◽  
Vol 50 (8) ◽  
pp. 475-477 ◽  
Author(s):  
G. V. Treyz ◽  
R. Beach ◽  
R. M. Osgood
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Direct Writing

High aspect-ratio SU-8 resist nano-pillar lattice by e-beam direct writing and its application for liquid trapping

2010 ◽  
Vol 87 (4) ◽  
pp. 663-667 ◽  
Author(s):  
D. López-Romero ◽  
C.A. Barrios ◽  
M. Holgado ◽  
M.F. Laguna ◽  
R. Casquel
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Direct Writing ◽  
Liquid Trapping

Direct-Writing of High-Aspect-Ratio Trenches in Silicon

1986 ◽  
Vol 75 ◽  
Author(s):  
G. V. Treyz ◽  
R. Beach ◽  
R. M. Osgood
Keyword(s):  
Experimental Data ◽  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Etch Rate ◽  
Crystalline Silicon ◽  
Etching Process ◽  
Direct Writing ◽  
Variable Curvature ◽  
Model Predictions

AbstractDeep trenches have been etched in crystalline silicon with polarization-controlled, variable-curvature walls. Scan speeds of up to 10mm/s have been demonstrated. A model of the etching process has been developed which is based on a local, melt-enhanced etch rate. Comparisons of model predictions and experimental data are presented.

Design and Fabrication of a Metallic Micro Heat Pipe Based on High-Aspect-Ratio Microchannels

2006 ◽  
Author(s):  
K. H. Oh ◽  
M. K. Lee ◽  
S. H. Jeong
Keyword(s):  
Aspect Ratio ◽  
Heat Pipe ◽  
Capillary Pressure ◽  
High Aspect Ratio ◽  
Scanning Speed ◽  
Cooling Capacity ◽  
Wet Etching ◽  
Direct Writing ◽  
Etching Technique ◽  
Micro Heat Pipe

The cooling capacity of a micro heat pipe is mainly governed by the magnitude of capillary pressure induced in the wick structure. For microchannel wicks, a higher capillary pressure is achievable for narrower and deeper channels. In this study, a metallic micro heat pipe adopting high-aspect-ratio microchannel wicks is fabricated. The micromachining of high-aspect-ratio microchannels is done using the laser-induced wet etching technique in which a focused laser beam irradiates the workpiece placed in a liquid etchant along a desired channel pattern. Because of the direct writing characteristic of the laser-induced wet etching method, no mask is necessary and the fabrication procedure is relatively simple. Deep microchannels of an aspect ratio close to 10 can be readily fabricated with little heat damage of the workpiece. The laser-induced wet etching process for the fabrication of high-aspect-ratio microchannels in 0.5mm thick stainless steel foil is presented in detail. The shape and size variations of microchannels with respect to the process variables, such as laser power, scanning speed, number of scans, and etchant concentration are closely examined. Also, the fabrication of a flat micro heat pipe based on the high-aspect-ratio microchannels is demonstrated.

Direct writing laser of high aspect ratio epoxy microstructures

2010 ◽  
Vol 21 (1) ◽  
pp. 017003 ◽  
Author(s):  
V J Cadarso ◽  
K Pfeiffer ◽  
U Ostrzinski ◽  
J B Bureau ◽  
G A Racine ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Direct Writing

A Note on High Aspect-Ratio SU-8 Micromechanical Structures Using Mask-Less Direct Laser Writing

2012 ◽  
Author(s):  
Siddharth Ghosh ◽  
G. K. Ananthasuresh
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Time Lags ◽  
Direct Writing ◽  
Laser Writing ◽  
Uv Lithography ◽  
Aspect Ratios ◽  
Direct Laser ◽  
Micromechanical Structures ◽  
Narrow Gaps

We report high aspect-ratio micromechanical structures made of SU-8 polymer, which is a negative photoresist. Mask-less direct writing with 405 nm laser is used to pattern spin-cast SU-8 films of thickness of more than 600 um. As compared with X-ray lithography, which helps pattern material to give aspect ratios of 1:50 or higher, laser writing is a less expensive and more accessible alternative. In this work, aspect ratios up to 1:30 were obtained on narrow pillars and cantilever structures. Deep vertical patterning was achieved in multiple exposures of the surface with varying dosages given at periodic intervals of sufficient duration. It was found that a time lag between successive exposures at the same location helps the material recover from the transient changes that occur during exposure to the laser. This gives vertical sidewalls to the resulting structures. The time-lags and dosages were determined by conducting several trials. The micromechanical structures obtained with laser writing are compared with those obtained with traditional UV lithography as well as e-beam lithography. Laser writing gives not only high aspect ratios but also narrow gaps whereas e-beam can only give narrow gaps over very small depths. Unlike traditional UV lithography, laser writing does not need a mask. Furthermore, there is no adjustment for varying the dosage in traditional UV lithography. A drawback of this method compared to UV lithography is that the writing time increases. Some test structures as well as a compliant microgripper are fabricated.

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