Microfabrication of refractive optics, waveguides, microfluidics, and high-aspect ratio structures realized by direct laser lithography

2009 ◽  
Author(s):  
Pierre Blanchet ◽  
Cécile Aubert ◽  
Nicolas Brillouet ◽  
Paul Coudray
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Laser Lithography ◽  
Direct Laser

High aspect ratio submicrometer two-dimensional structures fabricated by one-photon absorption direct laser writing

2014 ◽  
Vol 20 (10-11) ◽  
pp. 2097-2102 ◽  
Author(s):  
Mai Trang Do ◽  
Qinggele Li ◽  
Thi Thanh Ngan Nguyen ◽  
Henri Benisty ◽  
Isabelle Ledoux-Rak ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Photon Absorption ◽  
Two Dimensional ◽  
Direct Laser Writing ◽  
Laser Writing ◽  
Direct Laser

Direct laser beam interference patterning technique for fast high aspect ratio surface structuring

2015 ◽  
Author(s):  
Simonas Indrisiunas ◽  
Bogdan Voisiat ◽  
Airidas Žukauskas ◽  
Gediminas Račiukaitis
Keyword(s):  
Aspect Ratio ◽  
Laser Beam ◽  
High Aspect Ratio ◽  
Surface Structuring ◽  
Direct Laser ◽  
Patterning Technique

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.

The Interactions of Microhole Sidewall With Plasma induced by Femtosecond Laser Ablation in High-Aspect-Ratio Microholes

2012 ◽  
Vol 134 (1) ◽  
Author(s):  
Benxin Wu ◽  
Sha Tao ◽  
Shuting Lei
Keyword(s):  
Laser Ablation ◽  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Material Removal ◽  
Laser Energy ◽  
Spatial Scales ◽  
Femtosecond Laser Ablation ◽  
Plasma Energy ◽  
Direct Laser ◽  
Fs Laser

High-aspect-ratio microholes have many important applications, but their drilling is very challenging. Femtosecond (fs) laser ablation provides a potential solution, but involves many complicated physical processes that have not been well understood, which have hindered its practical application. One of these is that the plasma induced by laser ablation at the hole bottom will transfer some of its energy to the hole sidewall as it expands in the microhole. The plasma–sidewall interaction has been rarely studied in literature, and it is still not clear if or not the energy transferred from the plasma is sufficient to cause significant material removal from the sidewall. Direct time-resolved observations are extremely difficult due to the small temporal/spatial scales and the spatial constraint inside the hole, while the sidewall characterization after laser ablation is difficult to distinguish between the possible material removal due to plasma energy transfer and that due to direct laser energy absorption by the sidewall. In this paper, a physics-based model is applied as the investigation tool to study the plasma–sidewall interaction in fs laser drilling of high-aspect-ratio microholes. It has been found that for the studied conditions the energy transferred from the plasma is not sufficient to cause significant material removal from the sidewall through any thermally induced phase change process.

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