• Vacuum Magazine
• /
• v.2 no.1
• /
• pp.10-16
• /
• 2015

With the recognition of nanotechnology as one of the future strategic technologies, the R&D efforts have been performed under exclusive supports of governments and private sectors. At present, nanotechnology is at the focus of research and public attention in almost every advanced country including USA, Japan, and many others in EU. Keeping tracks of such technical trends, center for nanoscale mechatronics and manufacturing (CNMM) was established in 2002 as a part of national nanotechnology promotion policy led by ministry of science and technology (MOST) in Korea. It will hold widespread potential applications in electronics, optical electronics, biotechnology, micro systems, etc, with the promises of commercial visibility and competitiveness. In this paper, wafer scale multilayer nanoimprint lithography technology which is well-known the next generation lithography, roll-typed nanoimprint lithography (R-NIL), roll-typed liquid transfer imprint lithography (R-LTIL), the key technology for nanomanufacturing and nanoscale measurement technology will be introduced. Additionally, its applications and some achievements such as solar cell, biosensor, hard disk drive, and MOSFET, etc by means of the developed multilayer nanoimprint lithography system are introduced.

• The Transactions of the Korean Institute of Electrical Engineers C
• /
• v.55 no.5
• /
• pp.223-230
• /
• 2006

The reliability of imprint patterns molded by stamps for industrial application of nanoimprint lithography (NIL), is an important issue. Usually, defects can be produced by incomplete filling of negative patterns and the shrinkage phenomenon of polymers in conventional NIL. In this paper, the patterns that undergo a varied temperature or varied pressure period during the thermal NIL process have been investigated, with the goal of resolving the shrinkage and defective filling problems of polymers. The effects on the formation of polymer patterns in several profiles of imprint processes are also studied. Consequently, it is observed that more precise patterns are formed by the varied temperature (VT-NIL) or varied pressure (VP-NIL). The NIL (VT-NIL or VP-NIL) process has a free space compensation effect on the polymers in stamp cavities. From the results of the experiments, the polymer's filling capability can be improved. The VT-NIL is merged with the VP-NIL for the better filling property. The patterns that have been imprinted in the merged NIL are compared with the results of conventional NIL. In this study, the improvement in the reliability for results of thermal NIL has been achieved.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.24 no.10
• /
• pp.790-793
• /
• 2011

In this study, the surface modification for a silicon(Si) mold using $CHF_3$ inductively coupled plasma(ICP). The conditions under that plasma was treated a input ICP power 600 W, an operating gas pressure of 10 mTorr and plasma exposure time of 30 sec. The Si mold surface became hydrophobic after plasma treatment in order to $CF_x$(X= 1,2,3) polymer. However, as the de-molding process repeated, it was investigated that the contact angle of Si surface was decreased. So, we attempted to investigate the degradation mechanism of the accurate pattern transfer with increasing the count of the de-molding process using scanning electron microscope (SEM), contact angle, and x-ray photoelectron spectroscopy (XPS) analysis of Si mold surface.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.15 no.4
• /
• pp.1838-1843
• /
• 2014

Nanoimprint lithography (NIL) fabrication process is regarded as the main alternative to existing expensive photo-lithography in areas such as micro- and nano-electronics including optical components and sensors, as well as the solar cell and display device industries. Functional patterns, including anti-reflective moth-eye pattern, photonic crystal pattern, fabricated by NIL can improve the overall efficiency of such devices. To successfully imprint a nano-sized pattern, the process conditions such as temperature, pressure, and time should be appropriately selected. In this paper, a cavity-filling process of the moth-eye pattern during the thermal-NIL within the temperature range, where the polymer resist shows the viscoelastic behaviors with consideration of stress relaxation effect of the polymer, were investigated with three-dimensional finite element analysis. The effects of initial thickness of polymer resist and imprinting pressure on cavity-filling process has been discussed. From the analysis results it was found that the cavity filling can be completed within 100 s, under the pressure of more than 4 MPa.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.06a
• /
• pp.672-675
• /
• 2005

To imprint 70-nm wide line-patterns, we used a newly developed ultraviolet nanoimprint lithography (UV-NIL) process in which an elementwise patterned stamp (EPS), a large-area stamp, and pressurized air are used to imprint a wafer in a single step. For a single-step UV-NIL of a 4' wafer, we fabricated two identical $5'\times5'\times0.09'(W{\times}L{\times}H)$ quartz EPSs, except that one is with nanopatterns and the other without nanopatterns. Both of them consist of 16 small-area stamps, called elements, each of which is $10\;mm\;\times\;10\;mm$. UV-curable low-viscosity resin droplets were dispensed directly on each element of the EPSs. The volume and viscosity of each droplet are 3.7 nl and 7 cps. Droplets were dispensed in such a way that no air entrapment between elements and wafer occurs. When the droplets were fully pressed between ESP and wafer, some incompletely filled elements were observed because of the topology mismatch between EPS and wafer. To complete those incomplete fillings, pressurized air of 2 bar was applied to the bottom of the wafer for 2 min. Experimental results have shown that nanopatterns of the EPS were successfully transferred to the resin layer on the wafer.

• Tribology and Lubricants
• /
• v.22 no.4
• /
• pp.182-189
• /
• 2006

In this paper, the adhesion characteristics between a fused silica without or with an anti-sticking layer and a thermoplastic polymer film used in thermal NIL were investigated experimentally in order to identify the release performance of the anti-sticking layer. The anti-sticking layers were derived from fluoroalkylsilanes, (1H, 1 H, 2H, 2H-perfluorooctyl)trichlorosilane ($F_{13}-OTS$) and (3, 3, 3-trifluoropropyl)trichlorosilane (FPTS), and coated on the silica surface in vapor phase. The commercial polymers, mr-I 7020 and 8020 (micro resist technology, GmbH), for thermal NIL were spin-coated on Si substrate with a rectangular island which was fabricated by conventional microfabrication process to achieve small contact area and easy alignment of flat contact sur- faces. Experimental conditions were similar to the process conditions of thermal NIL. When the polymer film on the island was separated from the silica surface after imprint process, the adhesion force between the silica surface and the polymer film was measured and the surfaces of the silica and the polymer film after the separation were observed. As a result, the anti-sticking layers remarkably reduced the adhesion force and the surface damage of polymer film and the chain length of silane affects the adhesion characteristics. The anti-sticking layers derived from FPTS and $F_{13}-OTS$ reduced the adhesion force per unit area to 38% and 16% of the silica sur-faces without an anti-sticking layer, respectively. The anti-sticking layer derived from $F_{13}-OTS$ was more effective to reduce the adhesion, while both of the anti-sticking layers prevented the surface damages of the polymer film. Finally, it is also found that the adhesion characteristics of mr-I 7020 and mr-I 8020 polymer films were similar with each other.

• Journal of the Microelectronics and Packaging Society
• /
• v.23 no.4
• /
• pp.107-112
• /
• 2016

In this paper, the hydrophobic rough surfaces were prepared by employing a conventional nano-imprint lithography technique, and the effects of surface parameter, ratio of the top surface to the flat unit cell, on the impingement behaviors of liquid droplet were investigated to improve robustness of hydrophobic functionality. The critical height defined for the transition from rebound to fragmentation is measured by droplet impingement test in order to study dynamic behavior of an impinged droplet. It showed the critical height decreased with high surface parameter while it increased with low surface parameter. However, the critical height decreased again as surface parameter decreased further. Observed results suggest that the optimized surface pattern should be designed for the increased critical height.

• Korean Journal of Optics and Photonics
• /
• v.28 no.2
• /
• pp.53-58
• /
• 2017

This paper presents the design and fabrication of a planar nano-diffraction grating for an integrated miniature spectrometer module. The proposed planar nano-diffraction grating consists of nonuniform periods, to focus the reflected beams from the grating's surface, and an asymmetrical V-shaped groove profile, to provide uniform diffraction efficiency in the wavelength range from 400 to 650 nm. Also, to fabricate the nano-diffraction grating using low-cost UV-NIL technology, we analyzed the FT-IR spectrum of a uvcurable resin and optimized the conditions for the UV curing process. Then, we precisely fabricated the polymeric nano-diffraction grating within 5 nm in dimensional accuracy. The integrated spectrometer module using the fabricated polymeric planar nano-diffraction grating provides spectral resolution of 5 nm and spectral bandwidth of 250 nm. Our integrated spectrometer module using a polymeric planar nano-diffraction grating serves as a quick and easy solution for many spectrometric applications.

• Journal of the Microelectronics and Packaging Society
• /
• v.27 no.4
• /
• pp.55-60
• /
• 2020

The PERC photovoltaic (PV) modules installed in PV power plant are still reports potential-induced degradation (PID) degradation due to high voltage potential differences. This is because Na+ ions in the cover glass of PV modules go through the encapsulant (EVA) and transferred to the surface of solar cells. As positive charges are accumulated at the ARC (SiOx/SiNx) interface where many defects are distributed, shunt-resistance (Rsh) is reduced. As a result, the leakage current is increased, and decrease in solar cell's power output. In this study, to prevent of this phenomenon, a Moth-eye nanostructure was deposited on the rear surface of an optical film using Nano-Imprint Lithography method, and a solar mini-module was constructed by inserting it between the cover glass and the EVA. To analyze the PID phenomenon, a cell-level PID acceleration test based on IEC 62804-1 standard was conducted. Also analyzed power output (Pmax), efficiency, and shunt resistance through Light I-V and Dark I-V. As a result, conventional solar cells were decreased by 6.3% from the initial efficiency of 19.76%, but the improved solar cells with the Moth-eye nanostructured optical film only decreased 0.6%, thereby preventing the PID phenomenon. As of Moth-eye nanostructured optical film, the transmittance was improved by 4%, and the solar module output was improved by 2.5%.