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

This study aims at focusing a laser beam at the center of a microfluidic channel for optical bio-sensing applications thanks to the collective integration of tunable microlens arrays on VCSELs devices. High aspect-ratio polymer-based MOEMS are successfully fabricated on small-sized samples using thick dry photoresist films. Such dry films are easier to use and less expensive than standard thick SU-8 and can be efficiently stacked on fragile GaAs samples using a soft-thermal-printing technique. By combining double UV exposure and planar metallization, uniform fabrication of MOEMS arrays is enabled and fabricated devices exhibit reproducible electro-thermal behavior.

Download Full-text

Uniform subwavelength high-aspect ratio nanogratings on metal-protected bulk silicon produced by laser-induced periodic surface structuring

Applied Physics Letters ◽

10.1063/5.0075045 ◽

2021 ◽

Vol 119 (21) ◽

pp. 211106

Author(s):

Kirill Bronnikov ◽

Alexander Dostovalov ◽

Vadim Terentyev ◽

Sergey Babin ◽

Aleksey Kozlov ◽

...

Keyword(s):

Aspect Ratio ◽

High Aspect Ratio ◽

Bulk Silicon ◽

Periodic Surface ◽

Surface Structuring

Download Full-text

The Accuracy of Micro-molds Produced by a UV Laser Induced Polymerization

Journal of Engineering for Industry ◽

10.1115/1.2901954 ◽

1994 ◽

Vol 116 (3) ◽

pp. 370-376 ◽

Cited By ~ 6

Author(s):

K. Yamaguchi ◽

T. Nakamoto ◽

P. A. Abbay ◽

S. Mibu

Keyword(s):

Thin Films ◽

Aspect Ratio ◽

Laser Beam ◽

High Aspect Ratio ◽

Research Work ◽

Practical Method ◽

High Accuracy ◽

Uv Laser ◽

Ultraviolet Laser ◽

Absorption Of Light

This research work deals with the development of a simple and practical method for manufacturing metallic micromachine parts on the order of 0.01–1.0 mm in size. In this method, an ultraviolet laser beam is irradiated onto the surface of a liquid photopolymer material through a mask. The irradiated pattern is then developed to produce a solidified photopolymer mold. Finally, the metallic part is made by an electroforming process. This paper deals with the first process, the making of the photopolymer mold. At first, the accuracy of the mold is estimated by applying the theories of diffraction and absorption of light. Next, the accuracy is examined experimentally. The results show an accuracy of ± 1 μm can be obtained when a proximity transfer of 10 μm between the mask and the photopolymer surface is used. By stacking thin films, thick and high aspect ratio molds with a reasonably high accuracy are made.

Download Full-text

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

10.1117/12.808153 ◽

2009 ◽

Cited By ~ 1

Author(s):

Pierre Blanchet ◽

Cécile Aubert ◽

Nicolas Brillouet ◽

Paul Coudray

Keyword(s):

Aspect Ratio ◽

High Aspect Ratio ◽

Laser Lithography ◽

Direct Laser

Download Full-text

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

ASME 2012 International Manufacturing Science and Engineering Conference ◽

10.1115/msec2012-7413 ◽

2012 ◽

Cited By ~ 1

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.

Download Full-text