• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1532-1536
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• 2007

A plastic substrate with tiny rectangular pillars less than 100nm is injection molded to study pattern replication in injection molding. The size of the substrate is 50mm ${\times}$ 50mm and 1mm thick. The substrate has 9 patterned areas of which size is 2mm ${\times}$ 2mm respectively. The lengths of the pillars are 50nm, 100nm, 150nm and 200nm and the width and height are 50nm and about 100nm respectively. A pattern master is fabricated by e-beam writing using positive PR(photo resist) and then a nickel stamper replicated from the PR master by nickel electro-plating. Cr is deposited on the PR pattern master before nickel electro-plating as a conducting layer. Using this nickel stamper, several injection molding experiments are done to investigate effects of the injection molding parameters such as mold temperature, injection rate, packing pressure or pattern location on the replication of the patterns under 100nm.

• Journal of the Korean Society for Precision Engineering
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• v.24 no.4 s.193
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• pp.153-158
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• 2007

Recently nano imprint lithography to fabricate photonic crystal on polymer is preferred because of its simplicity and short process time and ease of precise manufacturing. But, the technique requires the precise mold as an imprinting tool for good replication. These molds are made of the silicon, nickel and quartz. But this is not desirable due to complex fabrication process, high cost. So, we describe a simple, precise and low cost method of fabricating PDMS stamp to make the photonic crystals. In order to fabricate the PDMS mold, we make the original pattern with designed hole array by finding the optimal electron beam writing condition. And then, we have tried to fabricate PDMS mold by the replica molding with ultrasonic vibration and pressure system. We have used the cleaning process to solve the detaching problem on the interface. Using these methods, we acquired the PDMS mold for photonic crystals with characteristics of a good replication. And the accuracy of replication shows below 1% in 440nm at diameter and in 610nm at lattice constant by dimensional analysis by SEM and AFM.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.10a
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• pp.305-310
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• 2004

The Hot Embossing Lithography(HEL) as a method for the fabrication of nanostructure with polymer is becoming increasingly important because of its simple process, low cost, high replication fidelity and relatively high throughput. In this study, we investigated the characteristics of hot embossing lithography as a nanoreplication technique. To grasp characteristics of nano patterning rheology by process parameters(embossing temperature, pressure and time), we have carried out various experiments by using the DVD(400nm pattern width) and Blu-ray nickel stamps(150nm pattern width). During the hot embossing process, we have observed the characteristics of the size effect. The quality of products made by hot embossing is affected by its cooling shrinkage. The demolding process at the glass transition temperature results in low quality because of the shrinkage of the polymer. Therefore, the quantification of the temperature condition is essential for the replication of high quality.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.10a
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• pp.173-174
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• 2006

• Journal of the Korean Society for Precision Engineering
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• v.23 no.4 s.181
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• pp.162-167
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• 2006

Hot embossing lithography(HEL) has the production advantage of comparatively few process step, simple operation, a relatively low cost for embossing tools(Si), and high replication accuracy for small features. In this paper, we considered the nano-molding characteristic according to molding parameters(temperature, pressure, times, etc) and induced a optimal molding condition using HEL. High precision nano-patter master with various shapes were designed and manufactured using the DRIE(Deep Reactive ion Etching), LPCVD(Low Pressure Chemical Vapor Deposition) and thermal oxidation process, and we investigated the molding characteristic of DVD and Blu-ray nickel stamp. We induced flow behaviors of polymer, rheology by shapes and sizes of the pattern through various molding experiments. Finally, with achieving nano-structure molding with high aspect ratio, we will secure a basic technology about the molding of large-area nano-pattern media.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.18 no.3
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• pp.307-314
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• 2009

Large area micro pattern replication has promising application potential in many areas. Rolling imprint process has been demonstrated as one of the most competitive processes for such micro pattern replication, because it has advantages in low cost, high throughput and high efficiency. In this paper, we developed a prototype of roll-to-flat(R2F) thermal imprint system for large area micro pattern replication process, which is one of the key processes in the fabrication of flexible displays. Experimental tests were conducted to evaluate the feasibility of system and the parameters' effect on the process, such as flat mold temperature, loading pressure and rolling speed. 100mm $\times$ 100mm stainless steel flat mold and commercially available polycarbonate sheets were used for the tests. The experimental results showed that the developed R2F system is suitable for fabrication of various micro devices with micro pattern over large area.

• Journal of the Microelectronics and Packaging Society
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• v.21 no.2
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• pp.85-89
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• 2014

We propose the new fabrication method of a 70 nm half-pitch wire grid polarizer with high performance using magnetic soft mold. The device is a form of aluminium gratings on a PET(Polyethylene phthalate) substrate whose size of $3cm{\times}3cm$ is compatible with a TFT_LCD(Tin Flat Transistor Liquid Crystal Display) panel. A magnetic soft mold with a pitch of 70 nm is fabricated using two-step replication method. As a result, we get a NWGP pattern which has 70.39 nm line width, 64.76 nm depth, 140.78 nm pitch, on substrate. The maximum and minimum transmittances of the NWGP at 800 nm are 75% and 10%, respectively. This work demonstrates a unique cost-effective solution for nanopatterning requirements in consumer electronics components.

• Proceedings of the KSME Conference
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• 2005.11a
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• pp.150.1-150.1
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• 2005

• Journal of the Korean Ceramic Society
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• v.40 no.6
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• pp.519-524
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• 2003

Porous carbon with high surface area and pore volume was prepared by a reverse replication process and its toluene equilibrium adsorption behavior was investigated. The preparation process of the porous carbon was composed of fellowing sub-processes in series: synthesis and template preparation of silica gel, impregnation and polymerization of DVB monomer in silica template, carbonization of DVB polymer in a silica-polymer composite, and HF-assisted selective etching of silica in carbon-silica composite. The prepared porous carbon was nano porous and had ultrahigh specific surface area (2007 ㎡/g) and large pore volume (3.07 ㎤/g). The nanoporous carbon showed rapid toluene adsorption rate and good toluene adsorption capacity, compared with a commercial Y-type zeolite. In the present study, a reverse replication process to prepare nanoporous carbons will be introduced and its application potential as a gas adsorbent will be discussed.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.676-679
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• 2005

Nano imprint Lithography (NIL) is regarded as one of the next-generation lithography technologies with EUV lithography, immersion lithography, Laser interference lithography. Because a Si wafer stamp and a quartz stamp, used to imprinting usually are very expensive and easily broken, it is suggested that master stamp is duplicated by PDMS and the PDMS stamp uses to imprint .For using the PDMS stamp, a thermally curable monomer resin was used for the imprinting process to lower pressure and temperature. As a result, NIL patterns were successfully fabricated.