• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 춘계학술대회 논문집 유기절연재료 방전 플라즈마연구회
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• pp.77-80
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• 2003

MEMS(Micro Electro Mechanical System) 기술에서 실리콘 식각기술의 중요성으로 플라즈마 식각기술의 개발이 꾸준히 진행되고 있다. 이중에서 ICP(Inductive Coupled Plasma)는 기존의 증착장치에 유도결합식 플라즈마를 추가로 발생시켜 증착막의 특성을 획기적으로 개선시키는 가장 최근에 개발된 기술이며, 이용에너지를 증가시키지 않고도 이용밀도를 높이고 이용업자들에 방향성을 가할 수 있는 새로운 플라즈마 기술로, 주로 MEMS 제조공정에 응용되고 있다. 본 연구에서는 STS-ICP $ASE^{HR}$을 이용하여 식각과 증착공정을 반복하여 식각을 하는 Bosch 식각에 관하여 연구하였다 STS-ICP $ASE^{HR}$ 장비의 Platen power, Coil power 및 Process pressure에 다양한 변화를 주어 각 변수에 따른 식각속도를 관찰하였다. 각 공정별 변수를 변화시킨 결과 Platen power 12W, Coil power 500W, 식각/Passivation Cycle 6/7sec 일 경우 식각속도는 $1.2{\mu}m$/min 이었고, Sidewall profile은 $90{\pm}0.7^{\circ}$로 나타나 매우 우수한 결과를 보였다.

• 한국결정성장학회지
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• 제11권3호
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• pp.106-111
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• 2001

The freestanding GaN substrates were grown by hydride vapor phase epitaxy (HVPE) on (0001) sapphire substrate and prepared by using laser induced lift-off. After a mechanical polishing on both Ga and N-surfaces of GaN films with 100$\mu\textrm{m}$ thick, their polarities have been investigated by using chemical etching in phosphoric acid solution, 3 dimensional surface profiler and Auger electron spectroscopy (AES). The composition of the GaN film measured by AES indicted that Ga and N terminated surfaces have the different N/Ga peak ratio of 0.74 and 0.97, respectively. Ga-face and N-face of GaN revealed quite different chemical properties: the polar surfaces corresponding to (0001) plane are resistant to a phosphoric acid etching whereas N-polar surfaces corresponding to(0001) are chemically active.

• 한국정밀공학회지
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• 제28권2호
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• pp.245-250
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• 2011

A high-resolution shadow mask, a nanostencil, is widely used for high resolution lithography. This high-resolution shadowmask is often fabricated by a combination of MEMS processes and focused ion beam (FIB) milling. In this study, FIB milling on 500-nm-thin SiN membrane was tested and characterized. 500 nm thick and $2{\times}2$ mm large membranes were made on a silicon wafer by micro-fabrication processes of LPCVD, photolithography, ICP etching and bulk silicon etching. A subsequent FIB milling enabled local membrane thinning and aperture making into the thinned silicon nitride membrane. Due to the high resolution of the FIB milling process, nanoscale apertures down to 60 nm could be made into the membrane. The nanostencil could be used for nanoscale patterning by local deposition through the apertures.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.1582-1584
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• 2008

This paper reports a simple fabrication method for creating the superhydrophobic polymer surface using a plasma etching. Generally, it is necessary for the superhydrophobic surfaces to have a rough structure on surface with the composition of the low surface energy. In this study, Poly(methyl methacrylate) (PMMA), poly(ethylene terephthalate) (PET), acrylonitrile butadiene styrene (ABS) with superhydrophobic surface were fabricated using $O_2$ plasma etching and vapor deposition with the fluoroalkylsilane self-assembled monolayers. The plasma treated polymer surfaces are covered with the nano-pillar shaped structures after treatment for $1{\sim}2min$. And these samples with FOTS SAMs coating are showed the superhydrophobicity having the water contact angle of around $150^{\circ}$ and sometimes around $180^{\circ}$ depending on the treatment time. Furthermore the nanostructured polymer is transparent for the visible light.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.1727-1732
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• 2008

We present a facile, yet versatile carbon nanofabrication method using electron beam lithography and resist pyrolysis. Various resist nanopatterns were fabricated using a negative electron beam resist, SAL-601, and were then subjected to heat treatment in an inert atmosphere to obtain carbon nanopatterns. Suspended carbon nanostructures were fabricated by wet-etching of an underlying sacrificial oxide layer. Free-standing carbon nanostructures, which contain 122 nm-wide, 15 nm-thick, and 2 ${\mu}m$-long nanobridges, were fabricated by resist pyrolysis and nanomachining processes. Electron beam exposure dose effects on resist thickness and pattern widening were studied. The thickness of the carbon nanostructures was thinned down by etching with oxygen plasma. An electrical biosensor utilizing carbon nanostructures as a conducting channel was studied. Conductance modulations of the carbon device due to streptavidin-biotin binding and pH variations were observed.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.1888-1891
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• 2003

In this paper, we proposed a new method to control the length of carbon nano tube in the single CNT probe. A single CNT probe was composed of a tungsten tip made by the electrochemical etching and carbon nano tube which was grown by CVD and prepared through the sonication. The two components were attached with the carbon tape. Since the length of CNT can not be controlled during the manufacturing, the post process is needed to shorten the CNT. In this paper, we proposed the method of electrochemical process. The process was done under the optical microscope and the results were checked by SEM. The diameter of the carbon nano tube used in this paper was about 130nm because the above process had to be done with the optical microscope. Using the method proposed in this paper, we can control the length of the nano tube tip.

• International Journal of Precision Engineering and Manufacturing
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• 제7권4호
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• pp.18-22
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• 2006

Although many efforts have been made in making nanometer-sized holes, there is still a major challenge in fabricating individual single-digit nanometer holes in a more controllable way for different materials, size distribution and hole shapes. In this paper we describe our efforts to use a top down approach in nanofabrication method to make single-digit nanoholes. There are three major steps towards the fabrication of a single-digit nanohole. 1) Preparing the freestanding thin film by epitaxial deposition and electrochemical etching. 2) Making sub-micro holes ($0.2{\mu}\;to\;0.02{\mu}$) by focused ion beam (FIB), electron beam (EB), atomic force microscope (AFM), and others methods. 3) Reducing the hole size to less than 10 nm by epitaxial deposition, FIB or EB induced deposition and micro coating. Preliminary work has been done on thin films (30 nm in thickness) preparation, sub-micron hole fabrication, and E-beam induced deposition. The results are very promising.

• 한국표면공학회지
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• 제24권4호
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• pp.215-221
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• 1991

Microstructure evolution during low temperature vapor deposition exhibits wel-developed columnar structure mainly owing to geometrical shadowing effect of surface roughness. It is concluded that this structure is concided with many theoretical models suggested so far. In case of aluminum nitride film deposition consisted of etching and nitriding step employing ECR plasma, the rougher the surface before etching, the finer and more cone-and-whisker structure can be developed. In turn, this fine structure affects the formation and growth of columnar as well as offers many sites available for mechanical lock-up. Conclusively, the formation of well-defined columnar structures depends on the initial surface roughness.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 춘계학술대회 논문집
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• pp.677-680
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• 1999

Rapid developing automation technology enhances the need of sensors. Among many materials, silicon has the advantages of electrical and mechanical property, Single-crystalline silicon has different piezoresistivity on 야fferent directions and a current leakage at elevated temperature, but poly-crystalline silicon has the possibility of controling resistivity using dopping ions, and operation at high temperature, which is grown on insulating layers. Each wafer has slightly different thicknesses that make difficult to obtain the precisely same thickness of a diaphragm. This paper deals with the fabrication process to make poly-crystalline silicon based pressure sensors which includes diaphragm thickness and wet-etching techniques for each layer. Diaphragms of the same thickness can be fabricated consisting of deposited layers by silicon bulk etching. HF etches silicon nitride, HNO$_3$+HF does poly -crystalline silicon at room temperature very fast. Whereas ethylenediamice based etchant is used to etch silicon at 11$0^{\circ}C$ slowly.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 추계학술대회 논문집 전기물성,응용부문
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• pp.101-102
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• 2006

PZT thin films, which are the representative ferroelectric materials in ferroelectric random access memory (FRAM), have some serious problem such as the imprint, retention and fatigue which ferroelectric properties are degraded by repetitive polarization. BL T thin film capacitors were fabricated by plasma etching, however, the plasma etching of BLT thin film was known to be very difficult. In our previous study, the ferroelectric materials such as PZT and BLT were patterned by chemical mechanical polishing (CMP) using damascene process to top electrode/ferroelectric material/bottom electrode. It is also possible to pattern the BLT thin film capacitors by CMP, however, the CMP damage was not considered in the experiments. The properties of BLT thin films were changed by the change of polishing pressure although the removal rate was directly proportional to the polishing pressure in CMP process.