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Proceedings Paper

Micromachining using a focused MeV proton beam for the production of high-precision 3D microstructures with vertical sidewalls of high orthogonality
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Paper Abstract

The production of high aspect ratio microstructures requires a lithographic technique capable of producing microstructures with vertical sidewalls. There are few techniques (eg proton beam micromachining, LIGA and Stereolithoghaphy) capable of producing high aspect ratio microstructures at sub-micron dimensions. In Proton Beam Micromachining (PBM), a high energy (eg 2 MeV) proton beam is focused to a sub-micron spot size and scanned over a resist material (eg SU-8 and PMMA). When a proton beam interacts with matter it follows an almost straight path, the depth of which is dependent on the proton beam energy. These features enable the production of multilevel microstructures with vertical sidewalls of high orthogonality. Proton beam micromachining is a fast direct write lithographic technique; in a few seconds a complicated pattern in an area of 400 x 400 micrometers 2 can be exposed down to a depth of 150 micrometers . These features make proton beam micromachining a technique of high potential for the production of high-aspect-ratio-structures at a much lower total cost than the LIGA process, which requires a synchrotron radiation source and precision masks. Research is currently under way to improve the process that employs the SU-8 negative photo-resist as a mold to electroplate Ni. Experiments have shown that post-bake and curing steps are not required in this SU-8 process, reducing the effects of cracking and internal stress in the resist. Plated Ni structures can be easily produced which are high quality negative copies of the SU-8 produced microstructures.

Paper Details

Date Published: 20 August 2001
PDF: 7 pages
Proc. SPIE 4343, Emerging Lithographic Technologies V, (20 August 2001); doi: 10.1117/12.436674
Show Author Affiliations
Jeroen Anton van Kan, National Univ. of Singapore (Singapore)
Andrew A. Bettiol, National Univ. of Singapore (Singapore)
K. Ansari, National Univ. of Singapore (Singapore)
Frank Watt, National Univ. of Singapore (Singapore)

Published in SPIE Proceedings Vol. 4343:
Emerging Lithographic Technologies V
Elizabeth A. Dobisz, Editor(s)

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