Soft-lithographic methods for the fabrication
of dielectrophoretic devices using molds by
proton beam writing
指導教授：許藝菊
報告者：陳亞維
Introduction
Experiments
Results and discussion
Conclusions
Keywords
 Soft-lithographic：透過多次翻模、轉移之技術來製
造出微米以及奈米的結構
 PBW：利用MeV能量的聚焦質子束對材料直接刻寫
微奈米尺度微結構
 Replica molding：利用PDMS灌注在母模上，待固化
後即可得到與母模相對應結構
 SU-8：負光阻，化學、熱穩定性高，高穿透性，
以及有良好的結構體之厚度以及深寬比
 Poly-dimethylsiloxane (PDMS) ：
 為目前生醫微機電系統(Bio-MEMS)常使用的材料
 低溫下依然具有柔軟、彈性與可塑性
Introduction
 In this paper, soft-lithographic methods for the
fabrication of 3D-DEP devices equipped with highaspect-ratio pillars,
 combined with a PDMS micro-fluidic channel
replicated from a SU-8 mold fabricated by PBW
Experiments
PBW of SU-8 layer on silica for patterning pillar arrays and a
mold for a micro-fluidic channel
Soft ithography of micro-fluidic channel by the SU-8 mold
Sealing the pillar arrays on silica with the PDMS, where the
silica substrate with pillar arrays is bonded to PDMS with a
micro-fluidic channel
Results and discussion
Fig. 3a shows a SEM image of the part
of pillar arrays with an area of 1.0 mm
80 µm by PBW onto a 15µm thick SU8 on a silica substrate
High-aspect-ratio pillars (rectangular of
2.5x6.8 µm in shape and 13 µm in
height) were observed with smooth and
vertical surface, as shown in Fig. 3b.
 Fig. 4a shows the SEM image of
a SU-8 mold with 200 µm in
width and 2.0 mm in length and
20 µm in height.
 Following the process illustrated
in Fig. 1b, the pattern of the SU-8
mold was successfully transferred
to PDMS, as shown in Fig. 4b.
 From an optical microscope
image in Fig. 5a
 Fig. 5b shows a photograph of
the DEP device with tubing at
inlet and outlet ports.
 Thanks to the plasma treatment,
the tight sealing was achieved
and no leakage was observed.
 Fig. 6a shows a SEM image of a SU-8 mold with arrays of holes with
rectangle of 7.0 X 5.3 µm^2 in shape and 12 µm in depth.
 As shown in Fig. 6b, the holes were successfully replicated to PDMS as
arrays of pillars.
 important to lower the adhesion force between the
SU-8 mold and PDMS and alignment of vertical
direction during separation to avoid fracture of
PDMS replica,
Conclusions
A soft lithography technique combined with
PBW was successfully applied to the fabrication
of the 3D-DEP device equipped with highaspect-ratio
channel.
pillar
arrays
in
micro-fluidic
 The most critical part of the process is pattern transfer
of the high-aspect pillar from the SU-8 mold to
PDMS. Replication of relatively low-aspect-ratio
pillar arrays was successful.
 Trials of successful replication of both pillar arrays
and a micro-fluidic channel are underway for DEP
devices with more complex structures.
Thank you for your
attention !