• Journal of Institute of Control, Robotics and Systems
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• v.10 no.7
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• pp.604-610
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• 2004

Ultraviolet-nanoimprint lithography (UV-NIL) is a promising method for cost-effectively defining nanoscale structures at room temperature and low pressure. Since the resolution of transferred nanostructures depends strongly upon that of nanostamps, the nanostamp fabrication technology is a key technology to UV-NIL. In this paper, a $5\times5\times0.09$ in. quartz stamp whose critical dimension is 377 nm was fabricated using the etching process in which a Cr film was employed as a hard mask for transferring nanostructures onto the quartz plate. To effectively apply the fabricated 5-in. stamp to UV-NIL on a 4-in. Si wafer, we have proposed a new UV-NIL process using a multi-dispensing method as a way to supply resist on a wafer. Experiments have shown that the multi-dispensing method can enable UV-NIL using a large-area stamp.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.04a
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• pp.38-42
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• 2002

In the recent, electro-rheological fluid has been used for micro polishing of the 3-dimensional micro-aspherical lens and some sectional parts with defects on the wide flat wafer. The ER fluid has the properties that its viscosity has drastic changed under some electric fields. Therefore, ER fluid can be applicable to the micro polishing fur some parts using these properties. In this paper, the experimental device has been constructed using the precision milling machine in order to micro polishing far some sectional parts of a 4 inches wafer It is consisted of a small steel electrode, a wafer fixture, DC10mA and 5KV power supply unit, and a controller unit. Using the ER experimental device, possibility of amending for wide flat wafer and micro polishing of some micro part has been analyzed.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.04a
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• pp.597-602
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• 2002

Ceramics are very difficult-to-cut materials because of its high strength and hardness. Their machining mechanism is characterized by cracking and brittle fracture. In this paper, to give good machinability to the ceramics, BN powders are added to Si$_3$N$_4$ by volume of 20, 25 and 30%. And the machiniability of the produced ceramics are tested using micro drilling system. Through required experimental works, it is shown that the micro drilling machinability is varied along with the volumetric percentage of BN powders. Also, it is verified that the obtained results can be used to develop new machinable ceramics of good material properties and machinability.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.04a
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• pp.27-33
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• 2004

Electro-theological fluid is recently used for the micro polishing of 3-dimensional micro-aspherical lens. It's also used for polishing small area defects on the wide flat wafer. Since ER fluid shows a behavior of viscosity changing under certain electric fields. micro polishing efficiency may be enhanced for certain cases. In this paper, a perfluorinated carbonyl fluoride oil based ER fluids was used to improve surface polishing rate and submicron-scale accuracy. As the polishing electrodes, micro size cylindrical tools had been used for maximizing the electric field. An experimental device, which was applied for micro polishing a number of wafers of 4inches in size and other workpiece. was made on a precision polishing system. It consisted of a steel electrode. a wafer fixture. l0㎃ current and DC 5㎸ power supply unit, and a controller unit. From the Experiments. the ER fluid is applicable for micro polishing of small parts.

• Proceedings of the KSME Conference
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• 2005.11a
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• pp.238.1-238.1
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• 2005

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1993.10a
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• pp.131-135
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• 1993

오늘날 전자산업, 광학기계,미세노즐 및 오리피스, 정밀공구,게이지, 고밀도 PCB 기판등 각종 산업에서 미세구멍 가공기술이 요구되고 있다. 이러한 구멍 가공에 사용될 수 있는 기술로는 드릴 가공의 기계적 가공방식 이외에 레이져가공,전자빔가공, 방전가공등의 열적가공방식과 전해가공,전해연마,화학부식의 화학적가공 방식이 있겠으나 생산성, 가공표면의 정도, 심혈가공의 어려움 등의 이유로 미세드릴을 이용한 기계적인 가공방법이 선호되고 있다. 본 연구에서는 미세구멍/가공시 가공토크에 미치는 중요 변수들의 영향을 실험을 통하여 조사하여 높은 절삭성을 발휘하는 동시에 공구의 파손도 피할 수 있는 조건을 제시하였다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.993-998
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• 2002

watches, air bearings and printed circuit hoards (PCB). However, it is not easy to determine optimum cutting conditions since the micro drilling process is very sensitive to various disturbances. Also, undesirable characteristics to optimize the micro drilling are small signal-to-noise ratios, drill wandering motions and high aspect ratios. Thus, in this study, experimental design methods are applied to determine optimum cutting conditions. Suing the methods, three cutting parameters, fred, step and curving speed are optimized to minimize thrust forces. Obtained conditions are verified through required experimental works. As the results, it is shown that the experimental methods can be applied to micro drilling processes to determine Optimum Cutting Conditions.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1535-1538
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• 2005

We present a mass productive and reproducible assembly technique of a single bundle of single-walled carbon nanotubes (sb-SWNTs) using dielectrophoresis (DEP). Gold electrodes with 10 gaps made via microlithography were used to align the carbon nanotubes (CNTs). The magnitude and type of applied electric field were investigated to verify their effects on CNT assembly. The optimum assembling conditions in which sb-SWNTs could be positioned at a desired site were experimentally identified, and the characteristics of the assembled sb-SWNTs were evaluated from AFM, Raman spectroscopy, and I-V curve. This assembly method has potential for applications such as gas sensors or electronic devices.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.05a
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• pp.452-457
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• 2003

As a fundamental study on developing elements with micro shape, micro mold parts machining and experiment of injection molding using it were performed. The ultra precision micro machining system with high functionality was fabricated, and utilized in the machining of micro parts. By using this machining system and micro end-mill tool, a micro circle column structure of high aspect ratio, diameter 60 $\mu\textrm{m}$, height 500 $\mu\textrm{m}$, was fabricated. And a micro lens molds were fabricated by using ball end-mill tool of 300 $\mu\textrm{m}$ diameter and diamond fly-cut tool of 150 $\mu\textrm{m}$ radius. A micro injection molding machine, which is clamping force 1.75 ton, injection capacity 2.8cc, was fabricated for injection molding experiment using micro molds. The injection molding experiment was performed by using the injection molding machine, micro cylinder structures and lens molds. This paper introduces these micro machining system and injection molding machine and demonstrates examples of injection molding using fabricated molds.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.8
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• pp.150-156
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• 2001

This paper deals with the theoretical estimation and its experimental verification of grinding wheel wear in surface grinding process. A theoretical formulation is provided to predict the grinding wheel wear in surface grinding. To validate the theoretical prediction, the grinding wheel wear is measured by using a laser scanning micrometer. The associated surface roughness and grinding farce are also investigated both theoretically and experimentally. Through a series of simulations and experiments, it is shown that the predictions are in good agreement with the experimental results.