TY - JOUR

T1 - Fabrication of high-aspect ratio SU-8 micropillar arrays

A1 - Amato,Letizia

A1 - Keller,Stephan S.

A1 - Heiskanen,Arto

A1 - Dimaki,Maria

A1 - Emnéus,Jenny

A1 - Boisen,Anja

A1 - Tenje,Maria

AU - Amato,Letizia

AU - Keller,Stephan S.

AU - Heiskanen,Arto

AU - Dimaki,Maria

AU - Emnéus,Jenny

AU - Boisen,Anja

AU - Tenje,Maria

PB - Elsevier BV

PY - 2012

Y1 - 2012

N2 - 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 (2.5μm spacing) with nominal height ⩾20μm and nominal diameter ⩽2.5μm (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 1.8μm, AR=11 and an improved temporal stability.

AB - 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 (2.5μm spacing) with nominal height ⩾20μm and nominal diameter ⩽2.5μm (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 1.8μm, AR=11 and an improved temporal stability.

KW - High-aspect ratio SU-8

KW - Micropillars

KW - UV photolithography

U2 - 10.1016/j.mee.2012.07.092

DO - 10.1016/j.mee.2012.07.092

JO - Microelectronic Engineering

JF - Microelectronic Engineering

SN - 0167-9317

VL - 98

SP - 483

EP - 487

ER -