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Fabrication of high aspect ratio SU-8 micropillar arrays

Amato, Letizia; Keller, Stephan S.; Heiskanen, Arto LU ; Dimaki, Maria; Emnéus, Jenny LU ; Boisen, Anja and Tenje, Maria LU (2012) In Microelectronic Engineering 98(Special issue MNE 2011 - Part II). p.483-487
Abstract
SU-8 is the preferred photoresist for development and fabrication of high aspect ratio (HAR) three dimensional patterns. However, processing of SU-8 is a challenging task, especially when the film thickness as well as the aspect ratio is increasing and the size of the features is close to the resolution limit of photolithography. This paper describes process optimization for the fabrication of dense SU-8 micropillar arrays (2.5 μm spacing) with nominal height ⩾20 μm and nominal diameter ⩽2.5 μm (AR ⩾8). Two approaches, differing in temperature, ramping rate and duration of the baking steps were compared as part of the photolithographic processing, in order to evaluate the effect of baking on the pattern resolution. Additionally, during the... (More)
SU-8 is the preferred photoresist for development and fabrication of high aspect ratio (HAR) three dimensional patterns. However, processing of SU-8 is a challenging task, especially when the film thickness as well as the aspect ratio is increasing and the size of the features is close to the resolution limit of photolithography. This paper describes process optimization for the fabrication of dense SU-8 micropillar arrays (2.5 μm spacing) with nominal height ⩾20 μm and nominal diameter ⩽2.5 μm (AR ⩾8). Two approaches, differing in temperature, ramping rate and duration of the baking steps were compared as part of the photolithographic processing, in order to evaluate the effect of baking on the pattern resolution. Additionally, during the post-processing, supercritical point drying and hard baking were introduced yielding pillars with diameter 1.8 μm, AR = 11 and an improved temporal stability. (Less)
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author
publishing date
type
Contribution to journal
publication status
published
subject
keywords
High-aspect ratio SU-8, Micropillars, UV photolithography
in
Microelectronic Engineering
volume
98
issue
Special issue MNE 2011 - Part II
pages
483 - 487
publisher
Elsevier
external identifiers
  • scopus:84865584866
ISSN
1873-5568
DOI
10.1016/j.mee.2012.07.092
language
English
LU publication?
no
id
30634cf3-5782-4ccc-9ca5-a781b764d34e (old id 3128750)
date added to LUP
2012-10-12 12:46:13
date last changed
2017-06-18 03:23:43
@article{30634cf3-5782-4ccc-9ca5-a781b764d34e,
  abstract     = {SU-8 is the preferred photoresist for development and fabrication of high aspect ratio (HAR) three dimensional patterns. However, processing of SU-8 is a challenging task, especially when the film thickness as well as the aspect ratio is increasing and the size of the features is close to the resolution limit of photolithography. This paper describes process optimization for the fabrication of dense SU-8 micropillar arrays (2.5 μm spacing) with nominal height ⩾20 μm and nominal diameter ⩽2.5 μm (AR ⩾8). Two approaches, differing in temperature, ramping rate and duration of the baking steps were compared as part of the photolithographic processing, in order to evaluate the effect of baking on the pattern resolution. Additionally, during the post-processing, supercritical point drying and hard baking were introduced yielding pillars with diameter 1.8 μm, AR = 11 and an improved temporal stability.},
  author       = {Amato, Letizia and Keller, Stephan S. and Heiskanen, Arto and Dimaki, Maria and Emnéus, Jenny and Boisen, Anja and Tenje, Maria},
  issn         = {1873-5568},
  keyword      = {High-aspect ratio SU-8,Micropillars,UV photolithography},
  language     = {eng},
  number       = {Special issue MNE 2011 - Part II},
  pages        = {483--487},
  publisher    = {Elsevier},
  series       = {Microelectronic Engineering},
  title        = {Fabrication of high aspect ratio SU-8 micropillar arrays},
  url          = {http://dx.doi.org/10.1016/j.mee.2012.07.092},
  volume       = {98},
  year         = {2012},
}