• Transactions of Materials Processing
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• v.19 no.2
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• pp.73-78
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• 2010

Recently, many researches on the development of super-hydrophobic surface have been concentrated on the fabrication of nano-patterned products. Nano-patterned mold is a key to replicate nano-patterned products by mass production process such as injection molding and UV molding. The present paper proposes the new fabricating method of nano-patterned mold at low cost. The nano-patterned mold was fabricated by electroforming the anodic aluminum oxide membrane filled with UV curable resin in nano-hole by capillary phenomenon. As a result, the final mold with nano-patterns which have the holes with the diameter of 100~200 nm was fabricated. Furthermore, the UV-molded products with clear nano- patterns which have the pillars with the diameter of 100~200nm were achieved.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.05a
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• pp.240-243
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• 2009

Recently, many researches on the development of super-hydrophobic and anti-reflective surfaces have been concentrated on the fabrication of nano-patterned products. The nano-patterned mold is a key to replicate nano-patterned products by mass production techniques such as injection molding and UV molding. The present paper proposes fabricating nano-patterned mold with cost-effective method. The nano-pattern molded was fabricated by electroforming the anodic aluminum oxide template without E-beam lithography. The final mold with nano-patterns showed the pores with the diameter of $100{\sim}120$ nm and the height of 150 nm was fabricated.

• Transactions of the Society of Information Storage Systems
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• v.1 no.2
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• pp.192-196
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• 2005

In this paper, we investigated the possibility of replicating patterned media by nano-injection molding process with a metallic nano-stamper. The original nano-master was fabricated by E-beam lithography and ICP etching process. The metallic nano-stamper was fabricated using a nanoimprint lithography and nano-electroforming process. The nano-patterned substrate was replicated using a nano-injection molding process without additional etching process. In nano-injection molding process, since the solidified layer, generated during the polymer filling, deteriorates transcribability of nano patterns by preventing the polymer melt from filling the nano cavities, an injection-mold system was constructed to actively control the stamper surface temperature using MEMS heater and sensors. The replicated polymeric patterns using nano-injection molding process were as small as 50 nm in diameter, 150 nm in pitch, and 50 nm in depth. The replicated polymeric patterns can be applied to high density patterned media.

• Transactions of Materials Processing
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• v.20 no.1
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• pp.23-28
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• 2011

For the fabrication of nano patterned products manufacturing a nano patterned mold is needed in advance. The nano patterned stamper was fabricated by electroforming the AAO master with nickel. The surface of nickel-plated stamper had nano-patterned holes with the diameter of 73 nm and the depth of 83 nm. Hot embossing was used for forming P3HT sheet and the process factors of hot embossing were closer as pressure, temperature and time. In the present paper hot embossing experiments were performed to find the main process conditions to affect the replication ratio of nano patterns on surface of P3HT sheet. As a result, main contributing factors for the replication ratio of hot embossed pattern could be sequentially enumerated as pressure, temperature and time.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1073-1077
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• 2003

This study aims to investigate the fabrication process of nano silicon mold using electron beam lithography (EBL) to generate the nanometer level patterns by nano-imprinting technology. the nano-patterned mold including 100mm pattern size has been fabricated by EBL with different doses ranged from 22 to 38 ${\mu}C/cm^2$ on silicon using the conventional polymethylmetharcylate(PMMA) resist. The silicon mold is fabricated with various patterns such as circles, rectangles, crosses, oblique lines and mixed forms, The effect of dosage on pattern density in EBL is discussed based on SEM (Scannning Electron Microscopy) analysis of fabricated molds. The mold surface is modified by hydrophobic fluorocarbon (FC) thin films to avoid the stiction during nano-imprinting process.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.05a
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• pp.513-516
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• 2008

We have replicated nanopillar arrays using injection molding process of active heating and cooling method by several peltier devices. The injection melding has a high accuracy ed good reproducibility that are essential for mass production at low cost. Conventional molding processes widely use the water-based mold heating and air cooling methods. However, in case of replication for nano-patterned structures, it caused several defects such as air-flow mark, non-fill, sticking and tearing. In this study, periodic nano-scale patterns are replicated by using injection molding with Peltier devices. Porous nano-scale patterns, which have pore diameter range from 120nm to 150nm, were fabricated by using anodizing process. Periodic nano-pore structures ( $20mm\;{\times}\;20mm$) were used as a mold stamp of injection molding. Finally, PMMA with nanopillar arrays was obtained by injection molding process. By using the Peltier devices, the temperature of locally adiabatic molds can be dramatically controlled and the quality of the molded patterns can be slightly improved.

• Macromolecular Research
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• v.17 no.4
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• pp.232-239
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• 2009

This paper describes the simple nanopatterning of proteins on polyelectrolyte surfaces using microcontact printing with a nanopatternable, hydrophilic composite nanomold. The composite nanomold was easily fabricated by blending two UV-curable materials composed of Norland Optical Adhesives(NOA) 63 and poly(ethylene glycol) dimethacrylate(PEG-DMA). NOA 63 provided stable nanostructure formation and PEG-DMA induced high wettability of proteins in the nanomold. Using the composite mold and functionalized surface with polyelectrolytes, the fluorescent, isothiocyanate-tagged, bovine serum albumin(FITC-BSA) was successfully patterned with 8 nm height and 500 nm width. To confirm the feasibility of the protein assay on a nanoscale, a glycoprotein-lectin assay was successfully demonstrated as a model system. As expected, the lectins correctly recognized the nano-patterned glycoproteins such as chicken ovalbumin. The simple preparation of composite nanomold and functionalized surface with a universal platform can be applied to various biomolecules such as DNA, proteins, carbohydrates, and other biomolecules on a nanoscale.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.411-411
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• 2012

Over the recent years, surface enhanced Raman spectroscopy (SERS) has dramatically grown as a label-free detecting technique with the high level of selectivity and sensitivity. Conventional SERS-active nanostructured layers have been deposited or patterned on rigid substrates such as silicon wafers and glass slides. Such devices fabricated on a flexible platform may offer additional functionalities and potential applications. For example, flexible SERS-active substrates can be integrated into microfluidic diagnostic devices with round-shaped micro-channel, which has large surface area compared to the area of flat SERS-active substrates so that we may anticipate high sensitivity in a conformable device form. We demonstrate fabrication of flexible SERS-active nanostructured substrates based on soft-lithography for simple, low-cost processing. The SERS-active nanostructured substrates are fabricated using conventional Si fabrication process and inkjet printing methods. A Si mold is patterned by photolithography with an average height of 700 nm and an average pitch of 200 nm. Polydimethylsiloxane (PDMS), a mixture of Sylgard 184 elastomer and curing agnet (wt/wt = 10:1), is poured onto the mold that is coated with trichlorosilane for separating the PDMS easily from the mold. Then, the nano-pattern is transferred to the thin PDMS substrates. The soft lithographic methods enable the SERS-active nanostructured substrates to be repeatedly replicated. Silver layer is physically deposited on the PDMS. Then, gold nanoparticle (AuNP) inks are applied on the nanostructured PDMS using inkjet printer (Dimatix DMP 2831) to deposit AuNPs on the substrates. The characteristics of SERS-active substrates are measured; topology is provided by atomic force microscope (AFM, Park Systems XE-100) and Raman spectra are collected by Raman spectroscopy (Horiba LabRAM ARAMIS Spectrometer). We anticipate that the results may open up various possibilities of applying flexible platform to highly sensitive Raman detection.

• KSTLE International Journal
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• v.6 no.2
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• pp.33-38
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• 2005

Submicron-scale patterns made of polymethyl methacrylate (PMMA) were fabricated on silicon-wafer using a capillarity-directed soft lithographic technique. Polyurethane acrylate (PUA) stamps (Master molds) were used to fabricate the patterns. Patterns with three different aspect ratios were fabricated by varying the holding time. The patterns fabricated were the negative replica of the master mold. The patterns so obtained were investigated for their adhesion and friction properties at nano-scale using AFM. Friction tests were conducted in the range of 0-80 nN. Glass (Borosilicate) balls of diameter 1.25 mm mounted on cantilever (Contact Mode type NPS) were used as tips. Further, micro-friction tests were performed using a ball-on-flat type micro-tribe tester, under reciprocating motion, using a soda lime ball (1 mm diameter) under a normal load of 3,000 mN. All experiments were conducted at ambient temperature ($24{\pm}1^{\circ}C$) and relative humidity ($45{\pm}5\%$). Results showed that the patterned samples exhibited superior tribological properties when compared to the silicon wafer and non-patterned sample (PMMA thin film) both at the nano and micro-scales, owing to their increased hydrophobicity and reduced real area of contact. In the case of patterns it was observed that their morphology (shape factor and size factor) was decisive in defining the real area of contact.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.284-284
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• 2010

We report a fabrication of 6, 13-bis(triisopropylsilylethynyl) (TIPS) pentacene nanowires that made on Si substrates by liquid bridge-nanotransfer molding (LB-nTM) with polyurethane acrylate (PUA) mold. LB-nTM is based on the direct transfer of various materials from a stamp to a substrate via a liquid bridge between them. In liquid bridge-transfer process, the liquid layer serves as an adhesion layer to provide good conformal contact and form covalent bonding between the TIPS-pentacene nanowire and the Si substrate. The patterned TIPS-Pentacene nanowires have been investigated by Atomic force microscopy (AFM), Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM) and electrical properties.