• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.1898-1899
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• 2005

반도체 집적회로 공정에서 사용되는 폴리이미드 포토레지스트(P12723, Dupont)를 감습막으로 사용하는 마이크로 습도센서 소자를 제작하였다. 마이크로 습도센서는 실리콘 웨이퍼 기판 위에 $SiO_2$ 박막을 건식열산화 공정으로 제작하고, Al 박막을 포토리소그라피 공정으로 패터닝 한 IDT (Interdigital Transducer)를 전극 위에 폴리이미드 포토레지스트를 공정변수를 다양하게 조절하면서 감습막으로 제작하였다. 폴리이미드 감습막은 스핀코팅법으로 제작하였으며, 회전수를 조절하여 두께를 변화시켰다. 완성된 마이크로 습도센서 소자의 상대습도 변화$(10{\sim}90% RH)$에 따른 정전용량 값 변화를 항온항습조 내에서 다양한 온도에서 HP4192A Impedance Analyzer를 사용하여 조사함으로써, 폴리이미드 포토레지스트를 사용하는 마이크로 정전용량형 습도센서의 제작 가능성을 검토하였다. 폴리이미드 정전용량형 마이크로 습도센서는 다양한 인가 전원 주파수에서 기준 센서로 사용된 상용 Vaisala Hygrometer와 유사한 감습특성 및 응답특성을 보였다.

• Journal of the Korean Society for Heat Treatment
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• v.36 no.4
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• pp.193-197
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• 2023

Transparent and conducting titanium (Ti) doped indium oxide (TIO) thin films were deposited on the poly-imide (PI) substrate with radio frequency magnetron sputtering and then electron irradiation was conducted on the TIO film's surface to investigate the effect electron irradiation on the crystallization and opto-electrical properties of the films. All x-ray diffraction (XRD) pattern showed two diffraction peaks of the In₂O₂ (431) and (444) planes with regardless of the electron beam irradiation energy. In the AFM analysis, the surface roughness of as deposited films was 3.29 nm, while the films electron irradiated at 700 eV, show a lower RMS roughness of 2.62 nm. In this study, the FOM of as deposited TIO films is 6.82 × 10^-3 Ω^-1, while the films electron irradiated at 500 eV show the higher FOM value of 1.0 × 10^-2 Ω^-1. Thus, it is concluded that the post-deposition electron beam irradiation at 500 eV is the one of effective methods of crystallization and enhancement of opto-electrical performance of TIO thin film deposited on the PI substrate.

• Membrane Journal
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• v.23 no.1
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• pp.1-11
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• 2013

Poly(ether imide) (PEI)-poly(dimethylsioxane) (PDMS) composite membranes and their modules were prepared, which are capable of selective $CO_2$ separation from the mixture gas. The gas flow rate, concentration, recovery ratio of $H_2$ and removal ratio of $CO_2$ outflowing by stage-cut were characterized at $25^{\circ}C$ and the constant pressure. In addition, to increase the recovery ratio of $H_2$, one stage, two stage series connection, and three stages series + parallel connection tests were carried out. When the stage-cut was 0.32 for the three stages connection operation, the concentration $H_2$ of the produced gas and the recovery ratio of $H_2$ was 97% and 85%, respectively. And also the removal ratio of $CO_2$ was 90% was obtained and the recycled gas concentration was similar with that of the feed gases.

• Membrane Journal
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• v.3 no.2
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• pp.60-69
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• 1993

The polyamic acid (PAA) based on 3,3', 4,4'-benzophenonetetracarboxylic dianhydride(BTDA)-3,3', 4,4'-dipheylsulfonetetracarboxylic dianhydride(BAPP), 2,2-bis(4-[4-aminophenoxyl]phenyl) propane(DSDA)-3,3', 4,4'-dipheylsulfonetetracarboxylic dianhydride(BAPP), and 3,3',4,4'-benzophenonetetracarboxylic dianhydride(BTDA)-4,4'-oxydianiline(4,4'-ODA) was synthesised. The casted PAA films were partially imidised and the permeation properties of these PAA films for $O_2$ and $N_2$ were investigated according to the degree of imidisation. When the degree of imidisation was increased by curing, the permeabilities of the PAA films were increased for a while and then decreased. These results show that the increase of gas permeation by the disappearence of strong hydrogen bond is larger than the decrease of gas permeation by the dense effect. The decrease of hydrogen bond between molecular chains of PAA suddenly increases the vibration of the chain to make holes but the compaction in polymer chain gradually decreases the gas permeation. The largest values of permeability of BTDA-BAPP, DSDA-BAPP and BTDA-4,4'-ODA film was 8.3, 0.3 and 0.8 barrer respectively, and the imidisation content corresponding to the values of the largest permeability was 37, 47 and 55% each. But the permselctivities of the PAA films were not changed by the variation of the degree of imidisation.

• Applied Chemistry for Engineering
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• v.17 no.3
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• pp.331-334
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• 2006

In this study, the ultra-fine fibers (UFs) having an alignment were prepared by electrospinning process, using different collectors made from various materials and collecting methods. A spinning solution was prepared by dissolving poly(amide-co-imide) (PAI) in NMP. The UFs were prepared by using various collectors and collecting methods, and the fibrous shapes were observed by SEM. As a result, a sort of materials of collectors and the collecting methods had not influenced on the average diameters of fibers but the forms of them. The just accumulated UFs on the collectors formed net structures, which had no alignment. On the contrary, the continuously collected UFs formed long fibers with alignment. It was found that the water collector played the roles of the fiber haul, temporary collector, moving path of fibers, and caused some friction between fibers and water, attributed to the formation of continuous UFs at a suitable collecting speed.

• Polymer(Korea)
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• v.38 no.5
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• pp.632-639
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• 2014

2,7-Dihydroxynaphthalene bis(trimellitate anhydride) (2,7-TA) was synthesized from trimellitic anhydride chloride and 2,7-dihydroxynaphthalene. Copolyimides (Co-PI) containing ester group were synthesized from 2,7-TA, pxylylenediamine, and 2,2'-bis(trifluoromethyl)benzidine (TFB). The Co-PI films were obtained from poly(amic acid) by solution casting through thermal imidization on a glass plate. The thermal property, gas permeation, and optical transparency of the Co-PI films with various TFB monomer contents were investigated. These Co-PIs could be solution-cast into a flexible and tough film. The cast Co-PI films exhibited high optical transparency with a cut-off wavelength of 370~395 nm in UV-vis. absorption and a low yellow index value of 3.55~7.63. The thermal property of Co-PI films increased linearly with increasing TFB content. However, the oxygen permeation and optical transparency of the Co-PI films was found to worsen with increasing TFB content.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.06a
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• pp.399-402
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• 1998

Electroluminescent(EL) devices based on organic thin films have attracted lots of interests in large-area light-emitting display. One of the problems of such device is a lifetime, where a degradation of the cell is possibly due to an organic layers thickness, morphology and interface with electrode. In this study, light-omitting organic electroluminescent devices were fabricated using Alq$_3$(8-hydroxyquinolinate aluminum) and TPD(N,N'-diphenyl-N,N'-bis(3-methylphenyl(1-1\`-biphenyl]-4,4'-diamine). Where Alq$_3$ is an electron-transport and emissive layer, TPD is a hole-transport layer. The cell structure is ITO/TPD/Alq$_3$/Al and the cell is fabricated by vacuum evaporation method. In a measurement of current-voltage characteristics, we obtained a turn-on voltage at about 9 V. We also investigated stability of the devices using buffer layer with blend of PEI (Poly ether imide) and TPD by varying mot ratios between ITO and Alq$_3$. In current-voltage characteristics measurement, we obtained the turn-on voltage at about 6 V and observed an anomalous behavior at 3∼4 V. And we used other buffer layer of PEDT(3,4-pyrazino-3',4'-ethylenedithio-2,2',5,5'-tetrathiafulvalenium) with ITO/PEDT/TPD/Alq$_3$Al structure. We observed a surface morphology by AFM(Atomic Force Microscopy), UV/visible absorption spectrum, and PL(Photoluminescence) spectrum. We obtained the UV/visible absorption peak at 358nm in TPD and at 359nm in Alq$_3$, and the PL peaks at 410nm in TPD and at 510nm in Alq$_3$. We also studied EL spectrum in the cell structure of ITO/(TPD+PEI)/Alq$_3$/Al.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.33-33
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• 2007

SoP-L 공정은 유전율이 상이한 재료를 이용하여 PCB 공정이 가능하고 다른 packaging 방법에 비해 공정 시간과 비용이 절약되는 잠정이 있다. 본 연구에서는 SoP-L 기술을 이용하여 Si 기판의 함몰에 판한 공정의 안정도와 함몰 시 제작된 때턴의 특성의 변화에 대해 관찰 하였다. Si 기판의 함몰에 Active device를 이용하여 특성의 변화를 살펴보고 공정의 안정도를 확립하려 했지만 Active device는 측정 시 bias의 확보와 특성의 민감한 변화로 인해 비교적 측정이 용이하고 공정의 test 지표를 삼기 위해 passive device 를 구현하여 함몰해 보았다. Passive device 의 제작 과정은 Si 기판 위에 spin coating을 통해 PI(Poly Imide)를 10um로 적층한 후에 Cr과 Au를 seed layer로 증착을 하였다. 그리고 photo lithography 공정을 통하여 photo resister patterning 후에 전해 Cu 도금을 거쳐 CPW 구조로 $50{\Omega}$ line 과 inductor를 형성하였다. 제작 된 passive device의 함몰 전 특성 추출 data와 SoP-L공정을 통한 함몰 후 추출 data 비교를 통해 특성의 변화와 공정의 안정도를 확립하였다. 차후 안정된 SoP-L 공정을 이용하여 Active device를 함몰 한다면 특성의 변화 없이 size 룰 줄이는 효과와 외부 자극에 신뢰도가 강한 기판이 제작 될 것으로 예상된다.

• Membrane Journal
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• v.25 no.4
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• pp.352-357
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• 2015

To determine the pervaporation separation characteristics of 1-butanol/water mixtures, PEI/PDMS hollow fiber membrane module commercialized by Airrane Co. was subjected to both lab and pilot tests. The 1% 1-butanol of 1-butanol/water feed mixture was used. The flux of $133g/m^2hr$ and separation factor of 23.4 at $30^{\circ}C$ were obtained whereas the $505g/m^2hr$ and 5.1 were measured at $50^{\circ}C$. When compared with the performance of the hollow fiber PDMS membrane by Nagasep Co., the higher flux of $10{\sim}20g/m^2hr$ was obtained by the module of Airrane Co. In order to realized the durability of Airrane Co. module, the long-term test of 35 days has been conducted and as a result, the flux $510{\sim}520g/m^2hr$ and separation factor 20~25 were maintained with the initial values.