Novel Silicon-containing Polynorbornenes as Photoresists for Extreme Ultraviolet Lithography

곽영제,Kwark, Young-Je The Korean Fiber Society 2006 한국섬유공학회지 Vol.43 No.5

Performance requirements for extreme ultraviolet (EUV) resists using photons at $\sim$13 nm may require the development of entirely new polymer platforms. Elements that are commonly used in photoresists at other wavelengths, such as oxygen and fluorine, are highly absorbing in this region making them problematic for EUV applications. We have devised new polymer platform for EUV lithography (EUVL). We have synthesized silicon-containing norbornene copolymers using ring-opening metathesis polymerization (ROMP). The norbornene monomers were prepared and copolymerized with a series of monomers having acid sensitive and polar groups, including nitrile, carboxylic acid, hydroxyl, and anhydride functions to achieve random copolymers with suitable properties for EUVL. From initial exposure studies using an EUV interferometer, we were able to produce patterns having a 150 nm pitch without additional optimization.

조절 라디칼 중합법을 이용한 PAN 함량이 많은 PEO-b-PAN 블록 공중합체의 합성

김태영,곽영제,Kim, Tae-Young,Kwark, Young-Je 한국섬유공학회 2015 한국섬유공학회지 Vol.52 No.1

Poly(ethylene oxide-b-acrylonitrile) (PEO-b-PAN) block copolymers were prepared as precursors to mesoporous carbons. Redox-initiated radical polymerization and controlled radical polymerization techniques, such as reversible addition-fragmentation chain transfer (RAFT) and activators regenerated by electron transfer atom-transfer radical polymerization (ARGET ATRP), were successfully applied to prepare PEO-b-PAN block copolymers with high PAN content. Radical polymerization of acrylonitrile (AN) using ceric ion as redox initiator gave block copolymers with PEO:PAN ratio of up to 1:38.4, but their high molecular weight and polydispersity index (PDI) indicated that the structure was not controlled. Therefore, in order to achieve better control on the structure of the PAN block, controlled radical polymerization techniques were used. Poly(ethylene oxide) with trithiocarbonate (PEO-CTA) and bromide (PEO-Br) end groups were synthesized as polymeric chain transfer agent for the RAFT process and as initiator for the ATRP process, respectively. The RAFT process of AN using PEO-CTA gave block copolymers with PAN block length 0.53-3.58 times that of the PEO block. Moreover, ARGET ATRP allowed to prepare block copolymers with a very high molecular weight of 72,000, while maintaining a PDI value as low as 1.20.

표면개시중합법을 이용한 셀룰로스 필터지의 젖음성 조절

양유미,최형민,곽영제,Yang, Yu-Mi,Choi, Hyung-Min,Kwark, Young-Je 한국섬유공학회 2008 한국섬유공학회지 Vol.45 No.5

The hydrophilic/hydrophobic nature of the cellulose could be tuned by introducing a polymer layer onto the surface using surface initiated polymerization techniques. Initiating groups for the polymerization could be immobilized by reacting 2-bromoisobutyrylbromide with the hydroxyl groups on cellulose. Thereafter, using atom transfer radical polymerization the modified cellulose was grafted with hydrophobic poly(methyl acrylate) (PMA), or with poly(N-isopropyl acrylamide) (PNIPAAm) which have been known for having lower critical solution temperature. We characterized the modified surface of cellulose using SEM-EDS and XPS, and FT-IR. The contact angles of the polymer grafted cellulose showed that the hydrophilic nature of cellulose surface was changed to hydrophobic after being grafted with PMA and to temperature dependent hydrophilic/hydrophobic with PNIPAAm.

Organosilicon LED Encapsulants Based on Polysiloxane and Polysilazane

은희천,허태환,곽영제,Eun, Hee Chun,Huh, Tae-Hwan,Kwark, Young-Je The Korean Fiber Society 2018 한국섬유공학회지 Vol.55 No.3

A mixture of polysiloxane (PSO) and polysilazane (PSZ) was used to prepare a crosslinked organosilicon material for use as an LED encapsulant. The crosslinking was conducted by using two different chemistries: platinum-catalyzed hydrosilylation and peroxide-initiated radical reaction. Successful crosslinking was confirmed by FT-IR spectroscopy, which showed decreased intensities of vinyl ($3,100cm^{-1}$) and hydrosilane ($2,140cm^{-1}$) peaks. The prepared films showed high transparency (>90% at 400 nm) because of the high compatibility between PSO and PSZ. The crosslinked organosilicon films showed higher hardness values when both PSO and PSZ were used at the same time, indicating higher crosslinking density.

가교된 PNIPAAm 표면층을 가지는 온도응답성 실리카 나노입자의 제조 및 특성분석

한태환,류광희,곽영제,Han, Tae-Hwan,Ryu, Kwang-Hee,Kwark, Young-Je 한국섬유공학회 2011 한국섬유공학회지 Vol.48 No.2

In this study, we prepared organic-inorganic hybrid nanoparticies with a core-shell structure using a surface-initiated polymerization technique. Initiators for the atom transfer radical polymerization were anchored onto the surface of silica nanoparticies, and from there N-isopropylacrylamide and methylene bisacrylamide were polymerized to form cross-linked polymeric shell layers. The thickness of the polymer layers was controlled by varying the reaction time. The thermal phase transition of the surface polymer layer was characterized by dynamic light scattering analysis, which showed reversible swelling/deswelling behavior between $25^{\circ}C$ and $40^{\circ}C$. Compared to the silica nanoparticies with linear polymer layers, the swelling/deswelling behavior was of a smaller degree, but it consistently exhibited similar size changes after repeated processes. HF etching of the silica nanoparticies with surface cross-linked polymer layers removed the silica core to render a hollow structure.

산처리된 MWNT의 고분자 전해질 거동에 관한 연구

은희천,조아라,곽영제,Eun, Hee-Chun,Cho, A-Ra,Kwark, Young-Je 한국섬유공학회 2011 한국섬유공학회지 Vol.48 No.5

Anionically charged MWNT with anionic carboxylic acid groups were mixed with cationic organic polymers, such as poly(allyamine hydrochloride) (PAH) and, poly(diallyldimethyl-ammonium chloride) (PDDA) to form polyelectrolyte complexes by coulombic interaction. The complexation behavior of the MWNT was affected by pH when mixed with PAH containing weak basic amine groups. By increasing the content of cationic polymer, the zeta potential of MWNT was increased from a negative values to a positive ones. With higher pH, the isoelectric point of anionic MWNT and cationic PAH increased and the saturated zeta potential value with high PAH content due to the less ionized MWNT and more ionized PAH. On the other hand, strong basic PDDA was less affected by changing pH and showed a similar isoelectric point and saturated zeta potential value with high PAH content. The complexation changed the dispersibility of MWNT in water, with the result that the MWNT was precipitated around the isoelectric point but then re-dispersed with higher cationic polymer content. HR-TEM images confirmed that excess PAH completely covered the MWNT.

유연한 디스플레이 소자의 보호막용 직접 패턴 형성이 가능한 POSS계 저유전 물질의 제조

임희은,고소연,곽영제,Im, Hee Eun,Ko, So-Yeon,Kwark, Young-Je 한국섬유공학회 2015 한국섬유공학회지 Vol.52 No.6

The passivation layer, which is located between a pixel electrode and a data electrode, must provide sufficiently low parasitic capacitance and sufficient electrical insulation to reduce cross talk and signal distortion. The present demand for passivation materials for next-generation displays has created interest in substitutes with low dielectric constant, high transmittance, thermal stability, and patternability; these requirements cannot be met by the silicon nitride layer and silicon dioxide used currently. To meet these requirements, negative-tone patterning systems containing polyhedral oligomeric silsesquioxane (POSS) were developed by adopting two different approaches: use of POSS in the polymeric matrix and in the crosslinker. The polymeric matrix, poly(methacryl isobutyl POSS-r-hydroxy styrene), showed improved dielectric property and thermal stability. However, the POSS content was limited owing to poor solubility. A POSS crosslinker with epoxy functional groups was used along with phenol group containing polymeric matrices; poly(4-hydroxy styrene). It was possible to pattern the POSS crosslinker system by irradiating it with UV light and subjecting it to subsequent thermal treatment. With increasing POSS content, the crosslinked materials showed increased transparency, higher thermal stability, and lower dielectric constant. The system could also be patterned by irradiating it with UV through a patterned mask.

무용매 공정과 직접 패턴이 가능한 실세스퀴옥산 탑 게이트 유기 트랜지스터용 게이트 유전체

권준선,이소윤,김도환,곽영제,Kwon, Jun-Seon,Lee, So Yoon,Kim, Do Hwan,Kwark, Young-Je 한국섬유공학회 2017 한국섬유공학회지 Vol.54 No.5

Top-gate organic field-effect transistors (OFET) have a problem that, when the gate dielectric layer is formed by solution processes, the underlying organic semiconductor layer is damaged. To solve this problem, we have developed organic-inorganic hybrid gate dielectric materials that can be prepared by a solvent-free method. To apply the solvent-free process, the dielectric material must be in a liquid state and can be later converted to solid to provide sufficient dimensional stability. Thus, we synthesized a liquid-phase poly(mercaptopropyl-co-vinyl)silsesquioxane (PMPVSSQ) that could be cross-linked by UV irradiation. The synthesized polymer was spin-coated on a silicon wafer after mixing with a photoinitiator and then cured through the thiol-ene reaction by UV irradiation to form a highly crosslinked film. In addition, a negative tone pattern was successfully formed by the conventional photolithography process. The leakage current of the dielectric film was lower than that of the conventional polymer gate dielectric due to the highly crosslinked structure. A top-gate OFET was fabricated using poly(3-hexylthiophene), a p-type organic semiconductor, and the transfer characteristics of the fabricated device showed excellent stable operation as a typical transistor. This showed that the dielectric forming process did not affect the semiconductor layer because no solvent was used.

전기방사를 이용한 실세스퀴아젠 나노섬유의 제조

강상욱,권오민,최형민,곽영제,Kang, Sang-Wook,Kwon, O-Min,Choi, Hyung-Min,Kwark, Young-Je 한국섬유공학회 2008 한국섬유공학회지 Vol.45 No.6

Nanofibers of phenylsilsesquiazanes (SSQZ), as a precursor of inorganic silicon nitride nanoweb, was prepared using the electrospinning process. The SSQZ was prepared by ammonolysis of phenyl trichlorosilane and condensation of the resulting aminosilanes. The molecular weight of resulting SSQZ increased with initial concentration of phenyl trichlorosilane, reaching plateau above 20wt% of the silane. When the SSQZ was electrospun alone, it did not form fiber even with 20wt% concentration of SSQZ. However, it was possible to prepare fibers by adding poly(ethylene oxide) (PEO) as a viscosity enhancer. The diameter the of electro spun fibers was modified by the total polymer content and the content of PEO. The best result was obtained when the total concentration of the polymer was in the range of 15 to 20 wt% while the SSQZ/PEO ratio was 95/5.

Sodium Lignosulfonate 표면처리가 탄산칼슘/폴리프로필렌 복합체에서 탄산칼슘의 분산에 미치는 영향

송준영(Junyoung Song),곽영제(Young-Je Kwark),정영진(Youngjin Jeong) 한국고분자학회 2015 폴리머 Vol.39 No.3

본 연구에서는 탄산칼슘(CaCO3)의 폴리프로필렌에 분산과 탄산칼슘 입자의 크기가 폴리프로필렌의 결정성에 미치는 영향을 연구하였다. 무기물로 충전된 고분자복합재료는 일반적으로 취성(brittleness)의 문제를 가지고 있으며, 이러한 문제는 주로 무기물입자의 크기와 분산에 의해서 영향을 받는다. 따라서 탄산칼슘의 분산성을 향상시키기 위한 방법으로 sodium lignosulfonate(SLS)의 함량을 달리하면서 탄산칼슘을 전처리하고 이에 따른 분산효과를 고찰하였다. 그 결과 3 wt%의 SLS로 처리된 탄산칼슘은 미처리 탄산칼슘에 비해 우수한 분산성을 보였으며, 열분석에서도 빠른 결정형성능을 보였다. 이러한 결정형성능은 탄산칼슘 입자의 크기에 의해서도 영향을 받았으며, 입자의 크기가 커지면 용융과 결정화 과정에서의 엔탈피 출입이 줄어드는 것으로 관찰되었다. 이러한 결과들은 무기물 고분자복합재료의 취성을 해결할 수 있는 단서를 제공한다고 할 수 있겠다. The dispersion of calcium carbonate (CaCO3) in polypropylene (PP) and the effect of CaCO3 size on the crystallinity of PP were studied. Polymer composite usually suffers from the brittleness when reinforced with inorganic fillers. The problem is generally related to the size and dispersion of fillers. First, the dispersion was studied for the nanosize CaCO3 with 15~40 nm average diameter. To enhance the dispersibility in PP, the surface of the CaCO3 was treated with sodium lignosulfonate (SLS). CaCO3/PP composites were prepared via melt compounding. The CaCO3 coated with more than 3 wt% SLS was uniformly distributed within the PP matrix, while the uncoated CaCO3 formed aggregated structures in the PP. Even with 30 wt%, the SLS-CaCO3 was well dispersed in the PP matrix. Also, the transition enthalpy of CaCO3/PP increased and the full-width of half maximum of the crystallization peak decreased regardless of SLS coating and size of CaCO3. However, the crystallinity of PP was more influenced by nano CaCO3. These results imply that the nano CaCO3 coated with SLS may reduce the brittleness of polymer composites.