Abstract
The aim of the project was to create high resolution stamps for thermal nanoimprint
applications. The creation of nanoridges with sub-100 nm resolutions was explored by
means of edge lithography via top-down routes, i.e. in combination with micromachining
technology. Edge lithography is an add-on technology which allows to use any lithographic
techniques for primary pattern denition.
The project started from the fabrication of SiO2 nanoridges by oxidizing vertical Si
edges using SiNx as the mask. Vertical Si sidewalls were created taking advantage of
Si <110> wafers and anisotropic Si etching by OPD4262. SiO2 nanoridges with sub-20
nm width were fabricated. In Chapter 2, we have presented the idea of reinforcing the
SiO2 nanoridges by an additional SiNx deposition to make the stamps reusable in T-NIL;
however, the over-deposition led to the loss of sub-20 nm resolution.
The fabrication of monocrystalline Si nanoridges by advanced edge lithography is demonstrated
in Chapter 3. The width of Si nanoridges was co-determined by Si anisotropic
etching, lateral retraction of SiNx and LOCOS. We have demonstrated the capability of
fabricating Si nanoridges with a width down to 10 nm by the advanced edge lithography.
In Chapter 4, the fabrication of multi-Si nanoridges has been explored and triple Si nanoridges
of 120 nm high and 40 nm wide with ca. 40 nm spacing have been created by a
repeated advanced edge lithography scheme. In this case, OPD 4262 was replaced by 20%
KOH used at room temperature and selective etching of SiNx and SiO2 was alternately
performed using 50% HF and hot H3PO4.
In Chapter 5, the fabrication of nanoridges was extended to arbitrary contours using
dry plasma etching methods to avoid the dependence of Si crystal orientation. A cryogenic
Si etching recipe was developed according to black silicon method. Two fabrication
schemes have been demonstrated capable of producing nanoridges with circular contours
with a width down to 60 nm. In the scheme where photoresist and Cr function as the
masking layers, Si nanoridges with perfect vertical sidewall prole but rough sidewall
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surface nish have been produced. Although Si nanoridges with slightly positive tapered
sidewalls are fabricated in the SU-8 scheme, the sidewall surface nish is smooth which
is benecial for nanoimprint applications.
We demonstrated the successful implementation of the monolithic Si nanoridges to
alternative nanofabrication approaches in Chapter 6. Assemblies of light harvesting antenna
complexes with a resolution of 80 nm have been created by thermal nanoimprint
lithography and self-assembly techniques. Composite PDMS-glass stamps with high resolution
line structures have been fabricated by both thermal nanoimprint lithography and
capillary force lithography. By using the high resolution composite PDMS-glass stamp,
we have demonstrated the fabrication of Au nanolines with a width of ca. 80 nm by
microcontact printing.
Original language | English |
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Award date | 27 May 2010 |
Place of Publication | Zutphen |
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Print ISBNs | 978-90-365-3036-1 |
DOIs | |
Publication status | Published - 27 May 2010 |