• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.80-81
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• 2012

Recently, one of the critical issues in the etching processes of the nanoscale devices is to achieve ultra-high aspect ratio contact (UHARC) profile without anomalous behaviors such as sidewall bowing, and twisting profile. To achieve this goal, the fluorocarbon plasmas with major advantage of the sidewall passivation have been used commonly with numerous additives to obtain the ideal etch profiles. However, they still suffer from formidable challenges such as tight limits of sidewall bowing and controlling the randomly distorted features in nanoscale etching profile. Furthermore, the absence of the available plasma simulation tools has made it difficult to develop revolutionary technologies to overcome these process limitations, including novel plasma chemistries, and plasma sources. As an effort to address these issues, we performed a fluorocarbon surface kinetic modeling based on the experimental plasma diagnostic data for silicon dioxide etching process under inductively coupled C4F6/Ar/O2 plasmas. For this work, the SiO2 etch rates were investigated with bulk plasma diagnostics tools such as Langmuir probe, cutoff probe and Quadruple Mass Spectrometer (QMS). The surface chemistries of the etched samples were measured by X-ray Photoelectron Spectrometer. To measure plasma parameters, the self-cleaned RF Langmuir probe was used for polymer deposition environment on the probe tip and double-checked by the cutoff probe which was known to be a precise plasma diagnostic tool for the electron density measurement. In addition, neutral and ion fluxes from bulk plasma were monitored with appearance methods using QMS signal. Based on these experimental data, we proposed a phenomenological, and realistic two-layer surface reaction model of SiO2 etch process under the overlying polymer passivation layer, considering material balance of deposition and etching through steady-state fluorocarbon layer. The predicted surface reaction modeling results showed good agreement with the experimental data. With the above studies of plasma surface reaction, we have developed a 3D topography simulator using the multi-layer level set algorithm and new memory saving technique, which is suitable in 3D UHARC etch simulation. Ballistic transports of neutral and ion species inside feature profile was considered by deterministic and Monte Carlo methods, respectively. In case of ultra-high aspect ratio contact hole etching, it is already well-known that the huge computational burden is required for realistic consideration of these ballistic transports. To address this issue, the related computational codes were efficiently parallelized for GPU (Graphic Processing Unit) computing, so that the total computation time could be improved more than few hundred times compared to the serial version. Finally, the 3D topography simulator was integrated with ballistic transport module and etch reaction model. Realistic etch-profile simulations with consideration of the sidewall polymer passivation layer were demonstrated.

• Textile Coloration and Finishing
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• v.8 no.2
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• pp.56-63
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• 1996

Low-temperature plasma treatment or sputter etching is of interest as one of the techniques to modify polymer surface. In this study, poly(ethylene terephthalate)(PET), nylon 6 and cotton fabrics dyed three black dyes were subjected to low-temperature argon plasma and also sputter etching. In relation to bathochromic effect, the surface characteristics of the treated fabrics and films were investigated by means of critical surface tension, SEM and ESCA measurement. The depth of shade of fabrics more increased by the sputter etching technique than argon plasma treatment. Many microcraters on the fiber surface formed by the sputter etching resulted in increase of surface area of the fiber and wettability, but the hydrophobic group was increased by the results of ESCA analysis. In particular the change in reflective index of the fibers was much more effective than the chemical composition of the fiber surface on increasing of the depth of shade.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.52 no.5
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• pp.206-206
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• 2003

It is hard to expect excellent electrical, mechanical and chemical properties from most of the composite materials presently used as insulators due to insufficient wettability property caused by the difference of interfacial properties between the matrix material and the reinforcer. Therefore, various interfacial coupling agents have been developed to improve the interfacial properties of composite materials. But if the wettable coupling agents are used outdoor for a long time, change in quality takes place in the coupling agents themselves, bringing about deterioration of the properties of the composite materials. In this study, glass surface was treated by plasma to examine the effect of dry interface treatment without coupling agent. It was identified that the optimum parameters for the best wettability of the samples at the time of generation of plasma were oxygen atmosphere, 0.1 torr of system pressure, 100 W of discharge power, and 3 minutes of discharge time. Also, the surface resistance rate and dielectric property were improved.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.52 no.5
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• pp.206-212
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• 2003

It is hard to expect excellent electrical, mechanical and chemical properties from most of the composite materials presently used as insulators due to insufficient wettability property caused by the difference of interfacial properties between the matrix material and the reinforcer. Therefore, various interfacial coupling agents have been developed to improve the interfacial properties of composite materials. But if the wettable coupling agents are used outdoor for a long time, change in quality takes place in the coupling agents themselves, bringing about deterioration of the properties of the composite materials. In this study, glass surface was treated by plasma to examine the effect of dry interface treatment without coupling agent. It was identified that the optimum parameters for the best wettability of the samples at the time of generation of plasma were oxygen atmosphere, 0.1 torr of system pressure, 100 W of discharge power, and 3 minutes of discharge time. Also, the surface resistance rate and dielectric property were improved.

• Proceedings of the KIEE Conference
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• 2002.11a
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• pp.176-178
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• 2002

Surface states of silicone polymer treated by plasma were investigated by the analysis by x-ray photoelectron spectroscopy(XPS) and surface voltage decay after corona charging. Plasma treatment causes the silica -like oxidative layer, which was confirmed with XPS, and lowers surface resistivity with increasing the plasma treatment time. Using the decay time constant of surface voltage, the calculated surface resistivity was compared with the value directly measured by voltage-current method using three electrodes system. A good agreement between two methods was obtained. In addition, we estimated the thermal activation energy for surface conduction, Based on our results, we could understand the relationship between surface chemical states and surface electrical properties.

• Journal of the Korean Vacuum Society
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• v.6 no.4
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• pp.321-325
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• 1997

Recently, photosensitive color filters have received much attention for their use in the liquid crystal display (LCD) industry. It is well known that chemical and physical properties of polymer surfaces can be modified by special surface treatments. In this work, we have studied the polymer surfaces of LCD blue color filters which were exposed to the UV light during photolithography. A better understanding of the irradiated polymer surfaces is required for the subsequent processes such as plasma etching, ITO electrode deposition, etc. The surface analysis has been undertaken using secondary ion mass spectrometry (SIMS), x-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM). A significant enrichment of the pigment component and roughening of surface with bubble-like feature have been observed at the modified polymer surface.

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.6
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• pp.797-803
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• 2013

In this paper, we fabricated insulator thin films by plasma polymerization method for organic thin film transistor's insulator layer. For improving the electrical characteristics of organic transistor, we treated the semiconductor thin film with $O_2$ plasma. As results, the surface energy of organic transistor was increased from $38mJ/m^2$ to $72mJ/m^2$ and the mobility of organic transistor was increased $0.057cm^2V^{-1}s^{-1}$, that is increased 29% average ratio. Therefore, we have known that oragnic transistor's mobility can improve with plasma treatment of semiconductor thin film's surface.

• Journal of Biomedical Engineering Research
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• v.28 no.4
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• pp.484-493
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• 2007

Two polymeric prodrugs of PGE1 (prodrugs IVg and PNg) were newly synthesized. The drug conjugation proceeded in quantitative yield without decomposition of PGE1 to PGA1. With two types conjugates, PEG-PGE1 and PN-PGE1 with different spacer groups, we first discovered a possibility of slow release of PGE1 in blood circulatory system. PGE1 is conjugated with PEG and PN through the long alkylene spacers, and their availability as polymeric prodrugs is evaluated. Their drug-releasing behavior was examined both in phosphate buffer (pH=7.4) and rat plasma. Each prodrug was known to be highly stabile in the buffer solution. The drug-releasing rate became much faster in rat plasma than in the buffer solution due to the acceleration by the plasma enzymes. The drug-release was found to reach a plateau in rat plasma because the released PGE1 or its derivatives may be captured or decomposed by the plasma proteins. The slower drug-releasing rate of pro drug PNg in rat plasma is reasonably attributed to the molecular aggregation due to the hydrophobic bonding between the PGE1 moieties and spacers.

• Journal of Integrative Natural Science
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• v.3 no.2
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• pp.89-95
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• 2010

It is still controversial where the improved stability of n-octadecyltriethoxysilane self-assembled monolayer (OTE SAM) on plasma-pretreated mica surface exactly originates from. To date, it has been well known that the extensive cross-polymerization between silane head-groups is a crucial factor for the outstanding mechanical strength of the monolayer. However, this study clearly showed that the stability comes not only from the cross-links but also, far more importantly, from the direct chemical bonds between silane headgroups and mica surface. To examine this phenomenon, n-octadecyltrichlorosilane monolayers were self-assembled on both untreated and plasma treated mica surfaces, and their adhesion properties at various physical conditions (relative humidity, high stress, and contact repetition) were investigated and compared through the use of the surface forces apparatus technique. It revealed that, in highly humid conditions (>90%RH), there is a substantial difference of stability between untreated and plasma treated cases and the plasma treated surface is mechanically much more stable. It obviously proves that the extensive chemical bonds indeed exist between silane head-groups and plasma treated mica surface and dramatically improve the mechanical stability of the OTE monolayer-coated mica substrate.

• Journal of Surface Science and Engineering
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• v.45 no.2
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• pp.75-80
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• 2012

A sputter-sublimation source was tested for high rate deposition of protective coating of PEMFC(polymer electrolyte membrane fuel cell) with high electrical conductivity and anti-corrosion capability by DC biasing of a metal rod immersed in inductively coupled plasma. A SUS(stainless steel) tube, rod were tested for low thermal conductivity materials and copper for high thermal conductivity ones. At 10 mTorr of Ar ICP(inductively coupled plasma) with 2.4 MHz, 300 W, the surface temperature of a SUS rod reached to $1,289^{\circ}C$ with a dc bias of 150 W (-706 V, 0.21 A) in 2 mins. For 10 min of sputter-sublimation, 0.1 gr of SUS rod was sputter-sublimated which is a good evidence of a high rate deposition source. ICP is used for sputter-sublimation of a target material, for substrate pre-treatment, film quality improvement by high energy particle bombardment and reactive deposition.