• Applied Microscopy
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• v.8 no.1
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• pp.49-52
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• 1978

Mask cells are distributed in the animal tissue, The bat subject has not been studied with the electron microscope, The material was fixed in 2.5% phosphate buffered glutaraldehyde for 24 hours at $4^{\circ}C$ and then post-fixed in phosphate buffered 1% osmium tetroxide for 2 hours at $4^{\circ}C$ and then the cleared tissues were embedded in Epon. The mast cell has numerous cytoplasmic processes projecting into the surrounding connective tissue. In general, the cytoplasmic granules showed ovoid, round, lunal or irregular shape, most of them were fine particulate substructure in texture. Especially, the granules was enclosed by the lamella structure.

• Journal of the Korean Vacuum Society
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• v.8 no.2
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• pp.116-120
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• 1999

Fe-Ni alloy thin films with about 3.5 $\mu\textrm{m}$ thickness were successfully grown on Al-killed steel substrates employing DC magnetron sputtering method, and then the4 film properties were characterized. The deposited film exhibited a fibre texture structure with the relationship of ${110}_\textrm{film}//{111}_\textrm{substrate}$. We found that the adhesion between the film and the substrate was fairly good considering no debonding behavior after the thermal cyclic test of 5,000 times from room temperature to $200^{\circ}C$. Also we found that the Fe-Ni alloy deposition induced a significant decrease of thermal expansion in the film processing, a new material system with much lower thermal expansion coefficient which can be applied more as shadow mask materials than an Al-killed steel sheet.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.351-354
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• 2004

This work presents a simple and cost-effective approach for maskless fabrication of positive-tone silicon master for the replica molding of hyperfine elastomeric channel. Positive-tone silicon masters were fabricated by a maskless fabrication technique using the combination of nanoscratch by Nanoindenter ⓡ XP and XOH wet etching. Grooves were machined on a silicon surface coated with native oxide by ductile-regime nanoscratch, and they were etched in a 20 wt％ KOH solution. After the KOH etching process, positive-tone structures resulted because of the etch-mask effect of the amorphous oxide layer generated by nanoscratch. The size and shape of the positive-tone structures were controlled by varying the etching time (5, 15, 18, 20, 25, 30 min) and the normal loads (1, 5 mN) during nanoscratch. Moreover, the effects of the Berkovich tip alignment (0, 45$^{\circ}$) on the deformation behavior and etching characteristic of silicon material were investigated.

• Transactions on Electrical and Electronic Materials
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• v.14 no.1
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• pp.28-31
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• 2013

A volcano shaped gated Si-FEA (silicon field emitter array) was simply fabricated using sputtering as a gate electrode deposition and lift-off for the removal of the oxide mask, respectively. Due to the limited step coverage of well-controlled sputtering and the high aspect ratio in Si dry etch caused by high RF power, it was possible to obtain Si FEAs with a stable volcano shaped gate structure and to realize the restriction of gate leakage current in field emission characteristics. For 100 tip arrays and 625 tip arrays, gate leakage currents were restricted to less than 1% of the anode current in spite of the volcano-shaped gate structure. It was also possible to keep the emitters stable without any failure between the Si cathode and gate electrode in field emission for a long time.

• Proceedings of the KIEE Conference
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• 2008.10a
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• pp.129-130
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• 2008

In this paper, optimal DRIE process conditions for fused quartz are experimentally determined by Taguchi method to develop high-performance inertial sensors based on the fused quartz material, which is known to have high Q-factors. Using Si layer as an etch mask, which was formed by previously developed bonding process of the fused quartz and Si wafer, fused quartz DRIE process was performed. Different 9 flow rate conditions of $C_4F_8$, $O_2$, He gas have been tested and the optimum combination of these factors was estimated. By this work, the ability to fabricate high aspect ratio fused quartz structure was confirmed.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.9-12
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• 2008

For the large-sized and post-ultra definition TFT-LCD, improved drivability is prerequisite not only for the integration of driving circuit on glass but also for the chargeability of each pixel. In order to meet required drivability, currently adopted process architecture and materials are modified for the RC delay reduction, including the drastic increase of gate bus thickness and its related solution for step coverage. We present new process architecture and material selection for the next generation TFT-LCD devices.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.10
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• pp.3113-3125
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• 1996

The objective of this study is to develop novel method named mechanical and chemical machining technique, which is capable of producing three dimensional patterns of few micrometers in dimension on a silicon wafer without the use of a mask. The strategy is to impart mechanical energy along the path of the pattern to be fabricated on a single crystal silicon by way on introdusing frictional interaction under controlled conditions. Then, the surface is preferentially etched to reveal the areas that have been mechanically energized. Upon completion of the etching process, the three dimensional pattern is produced on the silicon surface. Experiments have been conducted to identify the optimal tool material, geometery, as well as fabrication condition. The new technique introduced in this paper is significantly simpler than the conventional method which require sophisticated equipment and much time.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1069-1072
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• 2003

Ultraviolet-nanoimprint lithography (UV-NIL) is a promising nanoimprint method for cost-effectively defining nanometer scale structures at room temperature and low pressure. Nanostamp fabrication technology is a key technology for UV-NIL because fabricating a high resolution nanostamp is the first step for defining high resolution nanostructures in a substrate. We used quartz as an UV transparent stamp material for the UVNIL. A $5{\times}5{\times}0.09$ inch stamp was fabricated using the quartz etch process in which Cr film was used as a hard mask for transferring nanostructures into the quartz. In this paper, we describe the quartz etching process and discuss the results including SEM images.

• Journal of the Microelectronics and Packaging Society
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• v.21 no.2
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• pp.53-57
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• 2014

Thin glass (< 100 microns) is a promising material from which advanced interposers for high density electrical interconnects for 2.5D chip packaging can be produced. But thin glass is extremely brittle, so mechanical micromachining to create through glass vias (TGVs) is particularly challenging. In this article we show how laser processing using deep UV excimer lasers at a wavelength of 193 nm provides a viable solution capable of drilling dense patterns of TGVs with high hole counts. Based on mask illumination, this method supports parallel drilling of up over 1,000 through vias in 30 to $100{\mu}m$ thin glass sheets. (We also briefly discuss that ultrafast lasers are an excellent alternative for laser drilling of TGVs at lower pattern densities.) We present data showing that this process can deliver the requisite hole quality and can readily achieve future-proof TGV diameters as small $10{\mu}m$ together with a corresponding reduction in pitch size.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.3
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• pp.224-230
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• 2009

FIB has been commonly used as a very powerful tool in the semiconductor industry. It is mainly used for mask repair, device correction, failure analysis and IC error correction, etc. Currently, FIB is not being applied to the fabrication of the micro and nano-structured mold, because of low productivity. And also sputtering rate has been required to fabricate 3D shape. In the paper, we studied the FIB-Sputtering rate according to mold materials. And surface roughness characteristics had been analysed for micro or nano mold fabrication. Si wafer, Glassy Carbon, STAVAX and DLC that have been normally considered as good micro or nano mold materials were used in the study.